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Tracy L Huard - One of the best experts on this subject based on the ideXlab platform.
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the spitzer gould belt survey of large nearby interstellar clouds discovery of a dense embedded cluster in the Serpens aquila rift
The Astrophysical Journal, 2008Co-Authors: R A Gutermuth, Lori E Allen, Tyler L Bourke, Philip C Myers, S T Megeath, Brenda C Matthews, J K Jorgensen, J Di Francesco, D Wardthompson, Tracy L HuardAbstract:We report the discovery of a nearby, embedded cluster of young stellar objects, associated filamentary infrared dark cloud, and 4.5 μm shock emission knots from outflows detected in Spitzer IRAC mid-infrared imaging of the Serpens-Aquila Rift obtained as part of the Spitzer Gould Belt Legacy Survey. We also present radial velocity measurements of the region from molecular line observations obtained with the Submillimeter Array (SMA) that suggest the cluster is comoving with the Serpens Main embedded cluster 3° to the north. We therefore assign it the same distance, 260 pc. The core of the new cluster, which we call Serpens South, is composed of an unusually large fraction of protostars (77%) at high mean surface density (>430 pc−2) and short median nearest neighbor spacing (3700 AU). We perform basic cluster structure characterization using nearest neighbor surface density mapping of the YSOs and compare our findings to other known clusters with equivalent analyses available in the literature.
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the spitzer gould belt survey of large nearby interstellar clouds discovery of a dense embedded cluster in the Serpens aquila rift
arXiv: Astrophysics, 2007Co-Authors: R A Gutermuth, Lori E Allen, Tyler L Bourke, Philip C Myers, S T Megeath, Brenda C Matthews, J K Jorgensen, J Di Francesco, D Wardthompson, Tracy L HuardAbstract:We report the discovery of a nearby, embedded cluster of young stellar objects, associated filamentary infrared dark cloud, and 4.5 micron shock emission knots from outflows detected in Spitzer/IRAC mid-infrared imaging of the Serpens-Aquila Rift obtained as part of the Spitzer Gould Belt Legacy Survey. We also present radial velocity measurements of the region from molecular line observations obtained with the Submillimeter Array (SMA) that suggest the cluster is co-moving with the Serpens Main embedded cluster 3 degrees to the north. We therefore assign it the same distance, 260 pc. The core of the new cluster, which we call Serpens South, is composed of an unusually large fraction of protostars (77%) at high mean surface density (>430 pc^-2) and short median nearest neighbor spacing (3700 AU). We perform basic cluster structure characterization using nearest neighbor surface density mapping of the YSOs and compare our findings to other known clusters with equivalent analyses available in the literature.
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comparing star formation on large scales in the c2d legacy clouds bolocam 1 1 mm dust continuum surveys of Serpens perseus and ophiuchus
The Astrophysical Journal, 2007Co-Authors: Melissa L Enoch, Neal J Evans, J Glenn, Anneila I Sargent, Kaisa E Young, Tracy L HuardAbstract:We have undertaken an unprecedentedly large 1.1 mm continuum survey of three nearby star-forming clouds using Bolocam at the Caltech Submillimeter Observatory. We mapped the largest areas in each cloud at millimeter or submillimeter wavelengths to date: 7.5 deg2 in Perseus (Enoch and coworkers), 10.8 deg^2 in Ophiuchus (Young and coworkers), and 1.5 deg2 in Serpens with a resolution of 31", detecting 122, 44, and 35 cores, respectively. Here we report on results of the Serpens survey and compare the three clouds. Average measured angular core sizes and their dependence on resolution suggest that many of the observed sources are consistent with power-law density profiles. Tests of the effects of cloud distance reveal that linear resolution strongly affects measured source sizes and densities, but not the shape of the mass distribution. Core mass distribution slopes in Perseus and Ophiuchus (α = 2.1 ± 0.1 and 2.1 ± 0.3) are consistent with recent measurements of the stellar IMF, whereas the Serpens distribution is flatter (α = 1.6 ± 0.2). We also compare the relative mass distribution shapes to predictions from turbulent fragmentation simulations. Dense cores constitute less than 10% of the total cloud mass in all three clouds, consistent with other measurements of low star formation efficiencies. Furthermore, most cores are found at high column densities; more than 75% of 1.1 mm cores are associated with AV ~> 8 mag in Perseus, 15 mag in Serpens, and 20-23 mag in Ophiuchus.
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the spitzer c2d survey of large nearby interstellar clouds viii Serpens observed with mips
The Astrophysical Journal, 2007Co-Authors: Paul M Harvey, Luisa Rebull, Nicholas Chapman, Shihping Lai, Neal J Evans, Lucas A Cieza, William Spiesman, Tim Brooke, Tracy L Huard, Lori E AllenAbstract:We present maps of 1.5 deg2 of the Serpens dark cloud at 24, 70, and 160 μm observed with the Spitzer Space Telescope MIPS camera. We describe the observations and briefly discuss the data processing carried out by the c2d team on these data. More than 2400 compact sources have been extracted at 24 μm, nearly 100 at 70 μm, and four at 160 μm. We estimate completeness limits for our 24 μm survey from Monte Carlo tests with artificial sources inserted into the Spitzer maps. We compare source counts, colors, and magnitudes in the Serpens cloud to two reference data sets: a 0.50 deg 2 set on a low-extinction region near the dark cloud, and a 5.3 deg2 subset of the SWIRE ELAIS N1 data that was processed through our pipeline. These results show that there is an easily identifiable population of young stellar object candidates in the Serpens cloud that is not present in either of the reference data sets. We also show a comparison of visual extinction and cool dust emission illustrating a close correlation between the two and find that the most embedded YSO candidates are located in the areas of highest visual extinction.
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comparing star formation on large scales in the c2d legacy clouds bolocam 1 1 mm dust continuum surveys of Serpens perseus and ophiuchus
arXiv: Astrophysics, 2007Co-Authors: Melissa L Enoch, Neal J Evans, J Glenn, Anneila I Sargent, Kaisa E Young, Tracy L HuardAbstract:We have undertaken an unprecedentedly large 1.1 millimeter continuum survey of three nearby star forming clouds using Bolocam at the Caltech Submillimeter Observatory. We mapped the largest areas in each cloud at millimeter or submillimeter wavelengths to date: 7.5 sq. deg in Perseus (Paper I), 10.8 sq. deg in Ophiuchus (Paper II), and 1.5 sq. deg in Serpens with a resolution of 31", detecting 122, 44, and 35 cores, respectively. Here we report on results of the Serpens survey and compare the three clouds. Average measured angular core sizes and their dependence on resolution suggest that many of the observed sources are consistent with power-law density profiles. Tests of the effects of cloud distance reveal that linear resolution strongly affects measured source sizes and densities, but not the shape of the mass distribution. Core mass distribution slopes in Perseus and Ophiuchus (alpha=2.1+/-0.1 and alpha=2.1+/-0.3) are consistent with recent measurements of the stellar IMF, whereas the Serpens distribution is flatter (alpha=1.6+/-0.2). We also compare the relative mass distribution shapes to predictions from turbulent fragmentation simulations. Dense cores constitute less than 10% of the total cloud mass in all three clouds, consistent with other measurements of low star-formation efficiencies. Furthermore, most cores are found at high column densities; more than 75% of 1.1 mm cores are associated with Av>8 mag in Perseus, 15 mag in Serpens, and 20-23 mag in Ophiuchus.
Neal J Evans - One of the best experts on this subject based on the ideXlab platform.
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gaia dr2 confirms vlba parallaxes in ophiuchus Serpens and aquila
arXiv: Solar and Stellar Astrophysics, 2018Co-Authors: Gisela N Ortizleon, Neal J Evans, Sergio A Dzib, Marina Kounkel, Laurent Loinard, Luis F Rodriguez, P A B Galli, John J Tobin, Lee Hartmann, Cesar BricenoAbstract:We present Gaia-DR2 astrometry of a sample of YSO candidates in Ophiuchus, Serpens Main and Serpens South/W40 in the Aquila Rift, which had been mainly identified by their infrared excess with Spitzer. We compare the Gaia-DR2 parallaxes against published and new parallaxes obtained from our Very Long Baseline Array (VLBA) program GOBELINS. We obtain consistent results between Gaia and the VLBA for the mean parallaxes in each of the regions analyzed here. We see small offsets, when comparing mean values, of a few tens of micro-arcseconds in the parallaxes, which are either introduced by the Gaia zero-point error or due to a selection effect by Gaia toward the brightest, less obscured stars. Gaia-DR2 data alone conclusively places Serpens Main and Serpens South at the same distance, as we first inferred from VLBA data alone in a previous publication. Thus, Serpens Main, Serpens South and W40 are all part of the same complex of molecular clouds, located at a mean distance of 436+/-9 pc. In Ophiuchus, both Gaia and VLBA suggest a small parallax gradient across the cloud, and the distance changes from 144.2+/-1.3 pc to 138.4+/-2.6 pc when going from L1689 to L1688.
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comparing star formation on large scales in the c2d legacy clouds bolocam 1 1 mm dust continuum surveys of Serpens perseus and ophiuchus
The Astrophysical Journal, 2007Co-Authors: Melissa L Enoch, Neal J Evans, J Glenn, Anneila I Sargent, Kaisa E Young, Tracy L HuardAbstract:We have undertaken an unprecedentedly large 1.1 mm continuum survey of three nearby star-forming clouds using Bolocam at the Caltech Submillimeter Observatory. We mapped the largest areas in each cloud at millimeter or submillimeter wavelengths to date: 7.5 deg2 in Perseus (Enoch and coworkers), 10.8 deg^2 in Ophiuchus (Young and coworkers), and 1.5 deg2 in Serpens with a resolution of 31", detecting 122, 44, and 35 cores, respectively. Here we report on results of the Serpens survey and compare the three clouds. Average measured angular core sizes and their dependence on resolution suggest that many of the observed sources are consistent with power-law density profiles. Tests of the effects of cloud distance reveal that linear resolution strongly affects measured source sizes and densities, but not the shape of the mass distribution. Core mass distribution slopes in Perseus and Ophiuchus (α = 2.1 ± 0.1 and 2.1 ± 0.3) are consistent with recent measurements of the stellar IMF, whereas the Serpens distribution is flatter (α = 1.6 ± 0.2). We also compare the relative mass distribution shapes to predictions from turbulent fragmentation simulations. Dense cores constitute less than 10% of the total cloud mass in all three clouds, consistent with other measurements of low star formation efficiencies. Furthermore, most cores are found at high column densities; more than 75% of 1.1 mm cores are associated with AV ~> 8 mag in Perseus, 15 mag in Serpens, and 20-23 mag in Ophiuchus.
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the spitzer c2d survey of large nearby interstellar clouds viii Serpens observed with mips
The Astrophysical Journal, 2007Co-Authors: Paul M Harvey, Luisa Rebull, Nicholas Chapman, Shihping Lai, Neal J Evans, Lucas A Cieza, William Spiesman, Tim Brooke, Tracy L Huard, Lori E AllenAbstract:We present maps of 1.5 deg2 of the Serpens dark cloud at 24, 70, and 160 μm observed with the Spitzer Space Telescope MIPS camera. We describe the observations and briefly discuss the data processing carried out by the c2d team on these data. More than 2400 compact sources have been extracted at 24 μm, nearly 100 at 70 μm, and four at 160 μm. We estimate completeness limits for our 24 μm survey from Monte Carlo tests with artificial sources inserted into the Spitzer maps. We compare source counts, colors, and magnitudes in the Serpens cloud to two reference data sets: a 0.50 deg 2 set on a low-extinction region near the dark cloud, and a 5.3 deg2 subset of the SWIRE ELAIS N1 data that was processed through our pipeline. These results show that there is an easily identifiable population of young stellar object candidates in the Serpens cloud that is not present in either of the reference data sets. We also show a comparison of visual extinction and cool dust emission illustrating a close correlation between the two and find that the most embedded YSO candidates are located in the areas of highest visual extinction.
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comparing star formation on large scales in the c2d legacy clouds bolocam 1 1 mm dust continuum surveys of Serpens perseus and ophiuchus
arXiv: Astrophysics, 2007Co-Authors: Melissa L Enoch, Neal J Evans, J Glenn, Anneila I Sargent, Kaisa E Young, Tracy L HuardAbstract:We have undertaken an unprecedentedly large 1.1 millimeter continuum survey of three nearby star forming clouds using Bolocam at the Caltech Submillimeter Observatory. We mapped the largest areas in each cloud at millimeter or submillimeter wavelengths to date: 7.5 sq. deg in Perseus (Paper I), 10.8 sq. deg in Ophiuchus (Paper II), and 1.5 sq. deg in Serpens with a resolution of 31", detecting 122, 44, and 35 cores, respectively. Here we report on results of the Serpens survey and compare the three clouds. Average measured angular core sizes and their dependence on resolution suggest that many of the observed sources are consistent with power-law density profiles. Tests of the effects of cloud distance reveal that linear resolution strongly affects measured source sizes and densities, but not the shape of the mass distribution. Core mass distribution slopes in Perseus and Ophiuchus (alpha=2.1+/-0.1 and alpha=2.1+/-0.3) are consistent with recent measurements of the stellar IMF, whereas the Serpens distribution is flatter (alpha=1.6+/-0.2). We also compare the relative mass distribution shapes to predictions from turbulent fragmentation simulations. Dense cores constitute less than 10% of the total cloud mass in all three clouds, consistent with other measurements of low star-formation efficiencies. Furthermore, most cores are found at high column densities; more than 75% of 1.1 mm cores are associated with Av>8 mag in Perseus, 15 mag in Serpens, and 20-23 mag in Ophiuchus.
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the spitzer c2d survey of large nearby interstellar clouds viii Serpens observed with mips
arXiv: Astrophysics, 2007Co-Authors: Paul M Harvey, Luisa Rebull, Nicholas Chapman, Shihping Lai, Neal J Evans, Lucas A Cieza, William Spiesman, Tim Brooke, Tracy L Huard, Lori E AllenAbstract:We present maps of 1.5 square degrees of the Serpens dark cloud at 24, 70, and 160\micron observed with the Spitzer Space Telescope MIPS Camera. More than 2400 compact sources have been extracted at 24um, nearly 100 at 70um, and 4 at 160um. We estimate completeness limits for our 24um survey from Monte Carlo tests with artificial sources inserted into the Spitzer maps. We compare source counts, colors, and magnitudes in the Serpens cloud to two reference data sets, a 0.50 deg^2 set on a low-extinction region near the dark cloud, and a 5.3 deg^2 subset of the SWIRE ELAIS N1 data that was processed through our pipeline. These results show that there is an easily identifiable population of young stellar object candidates in the Serpens Cloud that is not present in either of the reference data sets. We also show a comparison of visual extinction and cool dust emission illustrating a close correlation between the two, and find that the most embedded YSO candidates are located in the areas of highest visual extinction.
Melissa L Enoch - One of the best experts on this subject based on the ideXlab platform.
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disk and envelope structure in class 0 protostars ii high resolution millimeter mapping of the Serpens sample
Astrophysical Journal Supplement Series, 2011Co-Authors: Melissa L Enoch, S Corder, G Duchene, D C J Bock, Alberto D Bolatto, T L Culverhouse, Woojin Kwon, James W Lamb, E M LeitchAbstract:We present high-resolution CARMA 230 GHz continuum imaging of nine deeply embedded protostars in the Serpens Molecular Cloud, including six of the nine known Class 0 protostars in Serpens. This work is part of a program to characterize disk and envelope properties for a complete sample of Class 0 protostars in nearby low-mass star-forming regions. Here, we present CARMA maps and visibility amplitudes as a function of uv-distance for the Serpens sample. Observations are made in the B, C, D, and E antenna configurations, with B configuration observations utilizing the CARMA Paired Antenna Calibration System. Combining data from multiple configurations provides excellent uv-coverage (4-500 kλ), allowing us to trace spatial scales from 10^2 to 10^4 AU. We find evidence for compact disk components in all of the observed Class 0 protostars, suggesting that disks form at very early times (t < 0.2 Myr) in Serpens. We make a first estimate of disk masses using the flux at 50 kλ, where the contribution from the envelope should be negligible, assuming an unresolved disk. The resulting disk masses range from 0.04 M_☉ to 1.7 M_☉, with a mean of approximately 0.2 M_☉. Our high-resolution maps are also sensitive to binary or multiple sources with separations ≳ 250 AU, but significant evidence of multiplicity on scales <2000 AU is seen in only one source.
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disk and envelope structure in class 0 protostars ii high resolution millimeter mapping of the Serpens sample
arXiv: Astrophysics of Galaxies, 2011Co-Authors: Melissa L Enoch, S Corder, G Duchene, D C J Bock, Alberto D Bolatto, T L Culverhouse, Woojin Kwon, James W Lamb, E M Leitch, D P MarroneAbstract:We present high-resolution CARMA 230 GHz continuum imaging of nine deeply embedded protostars in the Serpens Molecular Cloud, including six of the nine known Class 0 protostars in Serpens. This work is part of a program to characterize disk and envelope properties for a complete sample of Class 0 protostars in nearby low-mass star forming regions. Here we present CARMA maps and visibility amplitudes as a function of uv-distance for the Serpens sample. Observations are made in the B, C, D, and E antenna configurations, with B configuration observations utilizing the CARMA Paired Antenna Calibration System. Combining data from multiple configurations provides excellent uv-coverage (4-500 klam), allowing us to trace spatial scales from 1e2 to 1e4 AU. We find evidence for compact disk components in all of the observed Class 0 protostars, suggesting that disks form at very early times (t 250 AU, but significant evidence of multiplicity on scales <2000 AU is seen in only one source.
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disk and envelope structure in class 0 protostars i the resolved massive disk in Serpens firs 1
arXiv: Solar and Stellar Astrophysics, 2009Co-Authors: Melissa L Enoch, Michael M Dunham, S Corder, G DucheneAbstract:We present the first results of a program to characterize the disk and envelope structure of typical Class 0 protostars in nearby low-mass star forming regions. We use Spitzer IRS mid-infrared spectra, high resolution CARMA 230 GHz continuum imaging, and 2-D radiative transfer models to constrain the envelope structure, as well as the size and mass of the circum-protostellar disk in Serpens FIRS 1. The primary envelope parameters (centrifugal radius, outer radius, outflow opening angle, and inclination) are well constrained by the spectral energy distribution (SED), including Spitzer IRAC and MIPS photometry, IRS spectra, and 1.1 mm Bolocam photometry. These together with the excellent uv-coverage (4.5-500 klam) of multiple antenna configurations with CARMA allow for a robust separation of the envelope and a resolved disk. The SED of Serpens FIRS 1 is best fit by an envelope with the density profile of a rotating, collapsing spheroid with an inner (centrifugal) radius of approximately 600 AU, and the millimeter data by a large resolved disk with Mdisk~1.0 Msun and Rdisk~300 AU. These results suggest that large, massive disks can be present early in the main accretion phase. Results for the larger, unbiased sample of Class~0 sources in the Perseus, Serpens, and Ophiuchus molecular clouds are needed to determine if relatively massive disks are typical in the Class 0 stage.
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comparing star formation on large scales in the c2d legacy clouds bolocam 1 1 mm dust continuum surveys of Serpens perseus and ophiuchus
The Astrophysical Journal, 2007Co-Authors: Melissa L Enoch, Neal J Evans, J Glenn, Anneila I Sargent, Kaisa E Young, Tracy L HuardAbstract:We have undertaken an unprecedentedly large 1.1 mm continuum survey of three nearby star-forming clouds using Bolocam at the Caltech Submillimeter Observatory. We mapped the largest areas in each cloud at millimeter or submillimeter wavelengths to date: 7.5 deg2 in Perseus (Enoch and coworkers), 10.8 deg^2 in Ophiuchus (Young and coworkers), and 1.5 deg2 in Serpens with a resolution of 31", detecting 122, 44, and 35 cores, respectively. Here we report on results of the Serpens survey and compare the three clouds. Average measured angular core sizes and their dependence on resolution suggest that many of the observed sources are consistent with power-law density profiles. Tests of the effects of cloud distance reveal that linear resolution strongly affects measured source sizes and densities, but not the shape of the mass distribution. Core mass distribution slopes in Perseus and Ophiuchus (α = 2.1 ± 0.1 and 2.1 ± 0.3) are consistent with recent measurements of the stellar IMF, whereas the Serpens distribution is flatter (α = 1.6 ± 0.2). We also compare the relative mass distribution shapes to predictions from turbulent fragmentation simulations. Dense cores constitute less than 10% of the total cloud mass in all three clouds, consistent with other measurements of low star formation efficiencies. Furthermore, most cores are found at high column densities; more than 75% of 1.1 mm cores are associated with AV ~> 8 mag in Perseus, 15 mag in Serpens, and 20-23 mag in Ophiuchus.
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comparing star formation on large scales in the c2d legacy clouds bolocam 1 1 mm dust continuum surveys of Serpens perseus and ophiuchus
arXiv: Astrophysics, 2007Co-Authors: Melissa L Enoch, Neal J Evans, J Glenn, Anneila I Sargent, Kaisa E Young, Tracy L HuardAbstract:We have undertaken an unprecedentedly large 1.1 millimeter continuum survey of three nearby star forming clouds using Bolocam at the Caltech Submillimeter Observatory. We mapped the largest areas in each cloud at millimeter or submillimeter wavelengths to date: 7.5 sq. deg in Perseus (Paper I), 10.8 sq. deg in Ophiuchus (Paper II), and 1.5 sq. deg in Serpens with a resolution of 31", detecting 122, 44, and 35 cores, respectively. Here we report on results of the Serpens survey and compare the three clouds. Average measured angular core sizes and their dependence on resolution suggest that many of the observed sources are consistent with power-law density profiles. Tests of the effects of cloud distance reveal that linear resolution strongly affects measured source sizes and densities, but not the shape of the mass distribution. Core mass distribution slopes in Perseus and Ophiuchus (alpha=2.1+/-0.1 and alpha=2.1+/-0.3) are consistent with recent measurements of the stellar IMF, whereas the Serpens distribution is flatter (alpha=1.6+/-0.2). We also compare the relative mass distribution shapes to predictions from turbulent fragmentation simulations. Dense cores constitute less than 10% of the total cloud mass in all three clouds, consistent with other measurements of low star-formation efficiencies. Furthermore, most cores are found at high column densities; more than 75% of 1.1 mm cores are associated with Av>8 mag in Perseus, 15 mag in Serpens, and 20-23 mag in Ophiuchus.
Lori E Allen - One of the best experts on this subject based on the ideXlab platform.
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the spitzer gould belt survey of large nearby interstellar clouds discovery of a dense embedded cluster in the Serpens aquila rift
The Astrophysical Journal, 2008Co-Authors: R A Gutermuth, Lori E Allen, Tyler L Bourke, Philip C Myers, S T Megeath, Brenda C Matthews, J K Jorgensen, J Di Francesco, D Wardthompson, Tracy L HuardAbstract:We report the discovery of a nearby, embedded cluster of young stellar objects, associated filamentary infrared dark cloud, and 4.5 μm shock emission knots from outflows detected in Spitzer IRAC mid-infrared imaging of the Serpens-Aquila Rift obtained as part of the Spitzer Gould Belt Legacy Survey. We also present radial velocity measurements of the region from molecular line observations obtained with the Submillimeter Array (SMA) that suggest the cluster is comoving with the Serpens Main embedded cluster 3° to the north. We therefore assign it the same distance, 260 pc. The core of the new cluster, which we call Serpens South, is composed of an unusually large fraction of protostars (77%) at high mean surface density (>430 pc−2) and short median nearest neighbor spacing (3700 AU). We perform basic cluster structure characterization using nearest neighbor surface density mapping of the YSOs and compare our findings to other known clusters with equivalent analyses available in the literature.
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the spitzer gould belt survey of large nearby interstellar clouds discovery of a dense embedded cluster in the Serpens aquila rift
arXiv: Astrophysics, 2007Co-Authors: R A Gutermuth, Lori E Allen, Tyler L Bourke, Philip C Myers, S T Megeath, Brenda C Matthews, J K Jorgensen, J Di Francesco, D Wardthompson, Tracy L HuardAbstract:We report the discovery of a nearby, embedded cluster of young stellar objects, associated filamentary infrared dark cloud, and 4.5 micron shock emission knots from outflows detected in Spitzer/IRAC mid-infrared imaging of the Serpens-Aquila Rift obtained as part of the Spitzer Gould Belt Legacy Survey. We also present radial velocity measurements of the region from molecular line observations obtained with the Submillimeter Array (SMA) that suggest the cluster is co-moving with the Serpens Main embedded cluster 3 degrees to the north. We therefore assign it the same distance, 260 pc. The core of the new cluster, which we call Serpens South, is composed of an unusually large fraction of protostars (77%) at high mean surface density (>430 pc^-2) and short median nearest neighbor spacing (3700 AU). We perform basic cluster structure characterization using nearest neighbor surface density mapping of the YSOs and compare our findings to other known clusters with equivalent analyses available in the literature.
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the spitzer c2d survey of large nearby interstellar clouds viii Serpens observed with mips
The Astrophysical Journal, 2007Co-Authors: Paul M Harvey, Luisa Rebull, Nicholas Chapman, Shihping Lai, Neal J Evans, Lucas A Cieza, William Spiesman, Tim Brooke, Tracy L Huard, Lori E AllenAbstract:We present maps of 1.5 deg2 of the Serpens dark cloud at 24, 70, and 160 μm observed with the Spitzer Space Telescope MIPS camera. We describe the observations and briefly discuss the data processing carried out by the c2d team on these data. More than 2400 compact sources have been extracted at 24 μm, nearly 100 at 70 μm, and four at 160 μm. We estimate completeness limits for our 24 μm survey from Monte Carlo tests with artificial sources inserted into the Spitzer maps. We compare source counts, colors, and magnitudes in the Serpens cloud to two reference data sets: a 0.50 deg 2 set on a low-extinction region near the dark cloud, and a 5.3 deg2 subset of the SWIRE ELAIS N1 data that was processed through our pipeline. These results show that there is an easily identifiable population of young stellar object candidates in the Serpens cloud that is not present in either of the reference data sets. We also show a comparison of visual extinction and cool dust emission illustrating a close correlation between the two and find that the most embedded YSO candidates are located in the areas of highest visual extinction.
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the spitzer c2d survey of large nearby interstellar clouds viii Serpens observed with mips
arXiv: Astrophysics, 2007Co-Authors: Paul M Harvey, Luisa Rebull, Nicholas Chapman, Shihping Lai, Neal J Evans, Lucas A Cieza, William Spiesman, Tim Brooke, Tracy L Huard, Lori E AllenAbstract:We present maps of 1.5 square degrees of the Serpens dark cloud at 24, 70, and 160\micron observed with the Spitzer Space Telescope MIPS Camera. More than 2400 compact sources have been extracted at 24um, nearly 100 at 70um, and 4 at 160um. We estimate completeness limits for our 24um survey from Monte Carlo tests with artificial sources inserted into the Spitzer maps. We compare source counts, colors, and magnitudes in the Serpens cloud to two reference data sets, a 0.50 deg^2 set on a low-extinction region near the dark cloud, and a 5.3 deg^2 subset of the SWIRE ELAIS N1 data that was processed through our pipeline. These results show that there is an easily identifiable population of young stellar object candidates in the Serpens Cloud that is not present in either of the reference data sets. We also show a comparison of visual extinction and cool dust emission illustrating a close correlation between the two, and find that the most embedded YSO candidates are located in the areas of highest visual extinction.
R A Gutermuth - One of the best experts on this subject based on the ideXlab platform.
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abundant cyanopolyynes as a probe of infall in the Serpens south cluster forming region
Monthly Notices of the Royal Astronomical Society, 2013Co-Authors: Rachel Friesen, R A Gutermuth, Tyler L Bourke, J Di Francesco, Lia Medeiros, S Schnee, P C MyersAbstract:We have detected bright HC7N J = 21 20 emission toward multiple locations in the Serpens South cluster-forming region using the K-Band Focal Plane Array at the Robert C. Byrd Green Bank Telescope. HC7N is seen primarily toward cold filamentary structures that have yet to form stars, largely avoiding the dense gas associated with small protostellar groups and the main central cluster of Serpens South. Where detected, the HC7N abundances are similar to those found in other nearby starforming regions. Toward some HC7N ‘clumps’, we find consistent variations in the line centroids relative to NH3 (1,1) emission, as well as systematic increases in the HC7N non-thermal line widths, which we argue reveal infall motions onto dense filaments within Serpens South with minimum mass accretion rates of M � 2 5 M⊙ Myr −1 . The relative abundance of NH3 to HC7N suggests that the HC7N is tracing gas that has been at densities n � 10 4 cm −3 for timescales t . 1 2 × 10 5 yr. Since HC7N emission peaks are rarely co-located with those of either NH3 or continuum, it is likely that Serpens South is not particularly remarkable in its abundance of HC7N, but instead the serendipitous mapping of HC7N simultaneously with NH3 has allowed us to detect HC7N at low abundances in regions where it otherwise may not have been looked for. This result extends the known star-forming regions containing significant HC7N emission from typically quiescent regions, like the Taurus molecular cloud, to more complex, active environments.
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the properties of x ray luminous young stellar objects in the ngc 1333 and Serpens embedded clusters
arXiv: Solar and Stellar Astrophysics, 2010Co-Authors: E Winston, R A Gutermuth, S T Megeath, S J Wolk, L E Allen, B Spitzbart, Jesus HernandezAbstract:We present Chandra X-ray data of the NGC 1333 embedded cluster, combining these data with existing Chandra data, Sptizer photometry and ground based spectroscopy of both the NGC 1333 & Serpens North clusters to perform a detailed study of the X-ray properties of two of the nearest embedded clusters to the Sun. In NGC 1333, a total of 95 cluster members are detected in X-rays, of which 54 were previously identified with Spitzer. Of the Spitzer sources, we detect 23% of the Class I protostars, 53% of the Flat Spectrum sources, 52% of the Class II, and 50% of the Transition Disk YSOs. Forty-one Class III members of the cluster are identified, bringing the total identified YSO population to 178. The X-ray Luminosity Functions (XLFs) of the NGC 1333 and Serpens clusters are compared to each other and the Orion Nebula Cluster. Based on this comparison, we obtain a new distance for the Serpens cluster of 360+22/-13 pc. The X-ray luminosity was found to depend on the bolometric luminosity as in previous studies of other clusters, and that Lx depends primarily on the stellar surface area. In the NGC 1333 cluster, the Class III sources have a somewhat higher X-ray luminosity for a given surface area. We also find evidence in NGC 1333 for a jump in the X-ray luminosity between spectral types of M0 and K7, we speculate that this may result from the presence of radiative zones in the K-stars. The gas column density vs. extinction in the NGC 1333 was found to be N_H = 0.89 +/- 0.13 x 10^22 A_K, this is lower than expected of the standard ISM but similar to that found previously in the Serpens Cloud Core.
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the spitzer gould belt survey of large nearby interstellar clouds discovery of a dense embedded cluster in the Serpens aquila rift
The Astrophysical Journal, 2008Co-Authors: R A Gutermuth, Lori E Allen, Tyler L Bourke, Philip C Myers, S T Megeath, Brenda C Matthews, J K Jorgensen, J Di Francesco, D Wardthompson, Tracy L HuardAbstract:We report the discovery of a nearby, embedded cluster of young stellar objects, associated filamentary infrared dark cloud, and 4.5 μm shock emission knots from outflows detected in Spitzer IRAC mid-infrared imaging of the Serpens-Aquila Rift obtained as part of the Spitzer Gould Belt Legacy Survey. We also present radial velocity measurements of the region from molecular line observations obtained with the Submillimeter Array (SMA) that suggest the cluster is comoving with the Serpens Main embedded cluster 3° to the north. We therefore assign it the same distance, 260 pc. The core of the new cluster, which we call Serpens South, is composed of an unusually large fraction of protostars (77%) at high mean surface density (>430 pc−2) and short median nearest neighbor spacing (3700 AU). We perform basic cluster structure characterization using nearest neighbor surface density mapping of the YSOs and compare our findings to other known clusters with equivalent analyses available in the literature.
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the spitzer gould belt survey of large nearby interstellar clouds discovery of a dense embedded cluster in the Serpens aquila rift
arXiv: Astrophysics, 2007Co-Authors: R A Gutermuth, Lori E Allen, Tyler L Bourke, Philip C Myers, S T Megeath, Brenda C Matthews, J K Jorgensen, J Di Francesco, D Wardthompson, Tracy L HuardAbstract:We report the discovery of a nearby, embedded cluster of young stellar objects, associated filamentary infrared dark cloud, and 4.5 micron shock emission knots from outflows detected in Spitzer/IRAC mid-infrared imaging of the Serpens-Aquila Rift obtained as part of the Spitzer Gould Belt Legacy Survey. We also present radial velocity measurements of the region from molecular line observations obtained with the Submillimeter Array (SMA) that suggest the cluster is co-moving with the Serpens Main embedded cluster 3 degrees to the north. We therefore assign it the same distance, 260 pc. The core of the new cluster, which we call Serpens South, is composed of an unusually large fraction of protostars (77%) at high mean surface density (>430 pc^-2) and short median nearest neighbor spacing (3700 AU). We perform basic cluster structure characterization using nearest neighbor surface density mapping of the YSOs and compare our findings to other known clusters with equivalent analyses available in the literature.
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a combined spitzer and chandra survey of young stellar objects in the Serpens cloud core
The Astrophysical Journal, 2007Co-Authors: E Winston, R A Gutermuth, S T Megeath, S J Wolk, J Muzerolle, J L Hora, L E Allen, B SpitzbartAbstract:We present Spitzer and Chandra observations of the nearby (~260 pc) embedded stellar cluster in the Serpens cloud core. We observed, using Spitzer's IRAC and MIPS instruments, in six wavelength bands from 3 to 70 ?m, to detect thermal emission from circumstellar disks and protostellar envelopes and to classify stars using color-color diagrams and SEDs. These data are combined with Chandra observations to examine the effects of circumstellar disks on stellar X-ray properties. Young diskless stars were also identified from their increased X-ray emission. We have identified 138 YSOs in Serpens: 22 Class 0/I, 16 flat-spectrum, 62 Class II, 17 transition disk, and 21 Class III stars; 60 of these exhibit X-ray emission. Our primary results are the following: (1) 10 protostars detected previously in the submillimeter are detected at ? 1. This may be the result of grain growth through coagulation and/or the accretion of volatiles in the Serpens cloud core.
