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Kazuaki Ota - One of the best experts on this subject based on the ideXlab platform.
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the Spectral Energy Distribution of the redshift 7 1 quasar ulas j1120 0641
Astronomy and Astrophysics, 2015Co-Authors: R Barnett, S J Warren, Manda Banerji, R G Mcmahon, Paul C Hewett, D Mortlock, Chris Simpson, B P Venemans, Kazuaki OtaAbstract:We present new observations of the highest-redshift quasar known, ULAS J1120+0641, redshift z = 7.084, obtained in the optical, at near-, mid-, and far-infrared wavelengths, and in the sub-mm. We combine these results with published X-ray and radio observations to create the multiwavelength Spectral Energy Distribution (SED), with the goals of measuring the bolometric luminosity L bol , and quantifying the respective contributions from the AGN and star formation. We find three components are needed to fit the data over the wavelength range 0.12−1000 μ m: the unobscured quasar accretion disk and broad-line region, a dusty clumpy AGN torus, and a cool 47K modified black body to characterise star formation. Despite the low signal-to-noise ratio of the new long-wavelength data, the normalisation of any dusty torus model is constrained within ±40%. We measure a bolometric luminosity L bol = 2.6 ± 0.6 × 1047 erg s-1 = 6.7 ± 1.6 × 1013 L ⊙ , to which the three components contribute 31%,32%,3%, respectively, with the remainder provided by the extreme UV m. We tabulate the best-fit model SED. We use local scaling relations to estimate a star formation rate (SFR) in the range 60−270 M ⊙ /yr from the [C ii] line luminosity and the 158 μ m continuum luminosity. An analysis of the equivalent widths of the [C ii] line in a sample of z > 5.7 quasars suggests that these indicators are promising tools for estimating the SFR in high-redshift quasars in general. At the time observed the black hole was growing in mass more than 100 times faster than the stellar bulge, relative to the mass ratio measured in the local universe, i.e. compared to M BH /M bulge ≃ 1.4 × 10-3 , for ULAS J1120+0641 we measure Ṁ BH /Ṁ bulge ≃ 0.2.
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the Spectral Energy Distribution of the redshift 7 1 quasar ulas j1120 0641
Astronomy and Astrophysics, 2015Co-Authors: R Barnett, S J Warren, Manda Banerji, R G Mcmahon, Paul C Hewett, D Mortlock, Chris Simpson, B P Venemans, Kazuaki OtaAbstract:We present new observations of the highest-redshift quasar known, ULAS J1120+0641, redshift z = 7:084, obtained in the optical, at near-, mid-, and far-infrared wavelengths, and in the sub-mm. We combine these results with published X-ray and radio observations to create the multiwavelength Spectral Energy Distribution (SED), with the goals of measuring the bolometric luminosity Lbol, and quantifying the respective contributions from the AGN and star formation. We find three components are needed to fit the data over the wavelength range 0:12 1000 m: the unobscured quasar accretion disk and broad-line region, a dusty clumpy AGN torus, and a cool 47K modified black body to characterise star formation. Despite the low signal-to-noise ratio of the new long-wavelength data, the normalisation of any dusty torus model is constrained within 40%. We measure a bolometric luminosity Lbol = 2:6 0:6 10 47 erg s 1 = 6:7 1:6 10 13 L , to which the three components contribute 31%; 32%; 3%, respectively, with the remainder provided by the extreme UV 5:7 quasars suggests that these indicators are promising tools for estimating the SFR in high-redshift quasars in general. At the time observed the black hole was growing in mass more than 100 times faster than the stellar bulge, relative to the mass ratio measured in the local universe, i.e. compared to MBH=Mbulge’ 1:4 10 3 , for ULAS J1120+0641 we measure ˙ MBH= ˙ Mbulge’ 0:2.
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the Spectral Energy Distribution of the redshift 7 1 quasar ulas j1120 0641
arXiv: Astrophysics of Galaxies, 2014Co-Authors: R Barnett, S J Warren, Manda Banerji, R G Mcmahon, Paul C Hewett, D Mortlock, Chris Simpson, B P Venemans, Kazuaki OtaAbstract:We present new observations of the highest-redshift quasar known, ULAS J1120+0641, redshift $z=7.084$, obtained in the optical, at near-, mid-, and far-infrared wavelengths, and in the sub-mm. We combine these results with published X-ray and radio observations to create the multiwavelength Spectral Energy Distribution (SED), with the goals of measuring the bolometric luminosity $L_{\rm bol}$, and quantifying the respective contributions from the AGN and star formation. We find three components are needed to fit the data over the wavelength range $0.12-1000\,\mu$m: the unobscured quasar accretion disk and broad-line region, a dusty clumpy AGN torus, and a cool 47K modified black body to characterise star formation. Despite the low signal-to-noise ratio of the new long-wavelength data, the normalisation of any dusty torus model is constrained within $\pm40\%$. We measure a bolometric luminosity $L_{\rm bol}=2.6\pm0.6\times10^{47}\,$erg$\,$s$^{-1}=6.7 \pm 1.6\times10^{13}L_{\odot}$, to which the three components contribute $31\%,32\%,3\%$, respectively, with the remainder provided by the extreme UV $ 5.7$ quasars suggests that these indicators are promising tools for estimating the SFR in high-redshift quasars in general. At the time observed the black hole was growing in mass more than 100 times faster than the stellar bulge, relative to the mass ratio measured in the local universe, i.e. compared to ${M_{\rm BH}}/{M_{\rm bulge}} \simeq 1.4\times10^{-3}$, for ULAS J1120+0641 we measure ${\dot{M}_{\rm BH}}/{\dot{M}_{\rm bulge}} \simeq 0.2$.
Manda Banerji - One of the best experts on this subject based on the ideXlab platform.
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the Spectral Energy Distribution of the redshift 7 1 quasar ulas j1120 0641
Astronomy and Astrophysics, 2015Co-Authors: R Barnett, S J Warren, Manda Banerji, R G Mcmahon, Paul C Hewett, D Mortlock, Chris Simpson, B P Venemans, Kazuaki OtaAbstract:We present new observations of the highest-redshift quasar known, ULAS J1120+0641, redshift z = 7.084, obtained in the optical, at near-, mid-, and far-infrared wavelengths, and in the sub-mm. We combine these results with published X-ray and radio observations to create the multiwavelength Spectral Energy Distribution (SED), with the goals of measuring the bolometric luminosity L bol , and quantifying the respective contributions from the AGN and star formation. We find three components are needed to fit the data over the wavelength range 0.12−1000 μ m: the unobscured quasar accretion disk and broad-line region, a dusty clumpy AGN torus, and a cool 47K modified black body to characterise star formation. Despite the low signal-to-noise ratio of the new long-wavelength data, the normalisation of any dusty torus model is constrained within ±40%. We measure a bolometric luminosity L bol = 2.6 ± 0.6 × 1047 erg s-1 = 6.7 ± 1.6 × 1013 L ⊙ , to which the three components contribute 31%,32%,3%, respectively, with the remainder provided by the extreme UV m. We tabulate the best-fit model SED. We use local scaling relations to estimate a star formation rate (SFR) in the range 60−270 M ⊙ /yr from the [C ii] line luminosity and the 158 μ m continuum luminosity. An analysis of the equivalent widths of the [C ii] line in a sample of z > 5.7 quasars suggests that these indicators are promising tools for estimating the SFR in high-redshift quasars in general. At the time observed the black hole was growing in mass more than 100 times faster than the stellar bulge, relative to the mass ratio measured in the local universe, i.e. compared to M BH /M bulge ≃ 1.4 × 10-3 , for ULAS J1120+0641 we measure Ṁ BH /Ṁ bulge ≃ 0.2.
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the Spectral Energy Distribution of the redshift 7 1 quasar ulas j1120 0641
Astronomy and Astrophysics, 2015Co-Authors: R Barnett, S J Warren, Manda Banerji, R G Mcmahon, Paul C Hewett, D Mortlock, Chris Simpson, B P Venemans, Kazuaki OtaAbstract:We present new observations of the highest-redshift quasar known, ULAS J1120+0641, redshift z = 7:084, obtained in the optical, at near-, mid-, and far-infrared wavelengths, and in the sub-mm. We combine these results with published X-ray and radio observations to create the multiwavelength Spectral Energy Distribution (SED), with the goals of measuring the bolometric luminosity Lbol, and quantifying the respective contributions from the AGN and star formation. We find three components are needed to fit the data over the wavelength range 0:12 1000 m: the unobscured quasar accretion disk and broad-line region, a dusty clumpy AGN torus, and a cool 47K modified black body to characterise star formation. Despite the low signal-to-noise ratio of the new long-wavelength data, the normalisation of any dusty torus model is constrained within 40%. We measure a bolometric luminosity Lbol = 2:6 0:6 10 47 erg s 1 = 6:7 1:6 10 13 L , to which the three components contribute 31%; 32%; 3%, respectively, with the remainder provided by the extreme UV 5:7 quasars suggests that these indicators are promising tools for estimating the SFR in high-redshift quasars in general. At the time observed the black hole was growing in mass more than 100 times faster than the stellar bulge, relative to the mass ratio measured in the local universe, i.e. compared to MBH=Mbulge’ 1:4 10 3 , for ULAS J1120+0641 we measure ˙ MBH= ˙ Mbulge’ 0:2.
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the Spectral Energy Distribution of the redshift 7 1 quasar ulas j1120 0641
arXiv: Astrophysics of Galaxies, 2014Co-Authors: R Barnett, S J Warren, Manda Banerji, R G Mcmahon, Paul C Hewett, D Mortlock, Chris Simpson, B P Venemans, Kazuaki OtaAbstract:We present new observations of the highest-redshift quasar known, ULAS J1120+0641, redshift $z=7.084$, obtained in the optical, at near-, mid-, and far-infrared wavelengths, and in the sub-mm. We combine these results with published X-ray and radio observations to create the multiwavelength Spectral Energy Distribution (SED), with the goals of measuring the bolometric luminosity $L_{\rm bol}$, and quantifying the respective contributions from the AGN and star formation. We find three components are needed to fit the data over the wavelength range $0.12-1000\,\mu$m: the unobscured quasar accretion disk and broad-line region, a dusty clumpy AGN torus, and a cool 47K modified black body to characterise star formation. Despite the low signal-to-noise ratio of the new long-wavelength data, the normalisation of any dusty torus model is constrained within $\pm40\%$. We measure a bolometric luminosity $L_{\rm bol}=2.6\pm0.6\times10^{47}\,$erg$\,$s$^{-1}=6.7 \pm 1.6\times10^{13}L_{\odot}$, to which the three components contribute $31\%,32\%,3\%$, respectively, with the remainder provided by the extreme UV $ 5.7$ quasars suggests that these indicators are promising tools for estimating the SFR in high-redshift quasars in general. At the time observed the black hole was growing in mass more than 100 times faster than the stellar bulge, relative to the mass ratio measured in the local universe, i.e. compared to ${M_{\rm BH}}/{M_{\rm bulge}} \simeq 1.4\times10^{-3}$, for ULAS J1120+0641 we measure ${\dot{M}_{\rm BH}}/{\dot{M}_{\rm bulge}} \simeq 0.2$.
E Vardoulaki - One of the best experts on this subject based on the ideXlab platform.
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the vla cosmos 3 ghz large project average radio Spectral Energy Distribution of highly star forming galaxies
Astronomy and Astrophysics, 2019Co-Authors: Kresimir Tisanic, Vernesa Smolcic, J Delhaize, Mladen Novak, H T Intema, I Delvecchio, E Schinnerer, G Zamorani, M Bondi, E VardoulakiAbstract:We construct the average radio Spectral Energy Distribution (SED) of highly star-forming galaxies (HSFGs) up to z 4. Infrared and radio luminositie
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the vla cosmos 3 ghz large project average radio Spectral Energy Distribution of highly star forming galaxies
Astronomy and Astrophysics, 2019Co-Authors: Kresimir Tisanic, Vernesa Smolcic, J Delhaize, Mladen Novak, H T Intema, I Delvecchio, E Schinnerer, G Zamorani, M Bondi, E VardoulakiAbstract:We construct the average radio Spectral Energy Distribution (SED) of highly star-forming galaxies (HSFGs) up to z 4. Infrared and radio luminosities are bound by a tight correlation that is defined by the so- called q parameter. This infrared-radio correlation provides the basis for the use of radio luminosity as a star-formation tracer. Recent stacking and survival analysis studies find q to be decreasing with increasing redshift. It was pointed out that a possible cause of the redshift trend could be the computation of rest-frame radio luminosity via a single power-law assumption of the star-forming galaxies' (SFGs) SED. To test this, we constrained the shape of the radio SED of a sample of HSFGs. To achieve a broad rest-frame frequency range, we combined previously published Very Large Array observations of the COSMOS field at 1.4 GHz and 3 GHz with unpublished Giant Meterwave Radio Telescope (GMRT) observations at 325 MHz and 610 MHz by employing survival analysis to account for non- detections in the GMRT maps. We selected a sample of HSFGs in a broad redshift range (z ∈ [0.3, 4], SFR ≥ 100 M☉ yr-1) and constructed the average radio SED. By fitting a broken power-law, we find that the Spectral index changes from α1 = 0.42 ± 0.06 below a rest-frame frequency of 4.3 GHz to α2 = 0.94 ± 0.06 above 4.3 GHz. Our results are in line with previous low-redshift studies of HSFGs ( SFR > 10 M☉ yr-1) that show the SED of HSFGs to differ from the SED found for normal SFGs ( SFR < 10 M☉ yr-1). The difference is mainly in a steeper spectrum around 10 GHz, which could indicate a smaller fraction of thermal free-free emission. Finally, we also discuss the impact of applying this broken power-law SED in place of a simple power-law in K-corrections of HSFGs and a typical radio SED for normal SFGs drawn from the literature. We find that the shape of the radio SED is unlikely to be the root cause of the q - z trend in SFGs.
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the vla cosmos 3 ghz large project average radio Spectral Energy Distribution of highly star forming galaxies
arXiv: Astrophysics of Galaxies, 2018Co-Authors: Kresimir Tisanic, Vernesa Smolcic, J Delhaize, Mladen Novak, H T Intema, I Delvecchio, E Schinnerer, G Zamorani, M Bondi, E VardoulakiAbstract:We construct the average radio Spectral Energy Distribution (SED) of highly star-forming galaxies (HSFGs) up to z~4. Infrared and radio luminosities are bound by a tight correlation that is defined by the so-called q parameter. This infrared-radio correlation provides the basis for the use of radio luminosity as a star-formation tracer. Recent stacking and survival analysis studies find q to be decreasing with increasing redshift. It was pointed out that a possible cause of the redshift trend could be the computation of rest-frame radio luminosity via a single power-law assumption of the star-forming galaxies' (SFGs) SED.To test this, we constrained the shape of the radio SED of a sample of HSFGs. To achieve a broad rest-frame frequency range, we combined previously published VLA observations of the COSMOS field at 1.4 GHz and 3 GHz with unpublished GMRT observations at 325 MHz and 610 MHz by employing survival analysis to account for non-detections in the GMRT maps. We selected a sample of HSFGs in a broad redshift range (0.3 100M0/yr) and constructed the average radio SED. By fitting a broken power-law, we find that the Spectral index changes from $\alpha_1=0.42\pm0.06$ below a rest-frame frequency of 4.3 GHz to $\alpha_2=0.94\pm0.06$ above 4.3 GHz. Our results are in line with previous low-redshift studies of HSFGs (SFR>10M0/yr) that show the SED of HSFGs to differ from the SED found for normal SFGs (SFR<10M0/yr). The difference is mainly in a steeper spectrum around 10 GHz, which could indicate a smaller fraction of thermal free-free emission. Finally, we also discuss the impact of applying this broken power-law SED in place of a simple power-law in K-corrections of HSFGs and a typical radio SED for normal SFGs drawn from the literature. We find that the shape of the radio SED is unlikely to be the root cause of the q-z trend in SFGs.
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the vla cosmos 3 ghz large project average radio Spectral Energy Distribution of highly star forming galaxies
arXiv: Astrophysics of Galaxies, 2018Co-Authors: Kresimir Tisanic, Vernesa Smolcic, J Delhaize, Mladen Novak, H T Intema, I Delvecchio, E Schinnerer, G Zamorani, M Bondi, E VardoulakiAbstract:We construct the average radio Spectral Energy Distribution (SED) of highly star-forming galaxies (HSFGs) up to z~4. Infrared and radio luminosities are bound by a tight correlation that is defined by the so-called q parameter. This infrared-radio correlation provides the basis for the use of radio luminosity as a star-formation tracer. Recent stacking and survival analysis studies find q to be decreasing with increasing redshift. It was pointed out that a possible cause of the redshift trend could be the computation of rest-frame radio luminosity via a single power-law assumption of the star-forming galaxies' (SFGs) this http URL test this, we constrained the shape of the radio SED of a sample of HSFGs. To achieve a broad rest-frame frequency range, we combined previously published VLA observations of the COSMOS field at 1.4 GHz and 3 GHz with unpublished GMRT observations at 325 MHz and 610 MHz by employing survival analysis to account for non-detections in the GMRT maps. We selected a sample of HSFGs in a broad redshift range (0.3 100M0/yr) and constructed the average radio SED. By fitting a broken power-law, we find that the Spectral index changes from $\alpha_1=0.42\pm0.06$ below a rest-frame frequency of 4.3 GHz to $\alpha_2=0.94\pm0.06$ above 4.3 GHz. Our results are in line with previous low-redshift studies of HSFGs (SFR>10M0/yr) that show the SED of HSFGs to differ from the SED found for normal SFGs (SFR<10M0/yr). The difference is mainly in a steeper spectrum around 10 GHz, which could indicate a smaller fraction of thermal free-free emission. Finally, we also discuss the impact of applying this broken power-law SED in place of a simple power-law in K-corrections of HSFGs and a typical radio SED for normal SFGs drawn from the literature. We find that the shape of the radio SED is unlikely to be the root cause of the q-z trend in SFGs.
R Barnett - One of the best experts on this subject based on the ideXlab platform.
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the Spectral Energy Distribution of the redshift 7 1 quasar ulas j1120 0641
Astronomy and Astrophysics, 2015Co-Authors: R Barnett, S J Warren, Manda Banerji, R G Mcmahon, Paul C Hewett, D Mortlock, Chris Simpson, B P Venemans, Kazuaki OtaAbstract:We present new observations of the highest-redshift quasar known, ULAS J1120+0641, redshift z = 7.084, obtained in the optical, at near-, mid-, and far-infrared wavelengths, and in the sub-mm. We combine these results with published X-ray and radio observations to create the multiwavelength Spectral Energy Distribution (SED), with the goals of measuring the bolometric luminosity L bol , and quantifying the respective contributions from the AGN and star formation. We find three components are needed to fit the data over the wavelength range 0.12−1000 μ m: the unobscured quasar accretion disk and broad-line region, a dusty clumpy AGN torus, and a cool 47K modified black body to characterise star formation. Despite the low signal-to-noise ratio of the new long-wavelength data, the normalisation of any dusty torus model is constrained within ±40%. We measure a bolometric luminosity L bol = 2.6 ± 0.6 × 1047 erg s-1 = 6.7 ± 1.6 × 1013 L ⊙ , to which the three components contribute 31%,32%,3%, respectively, with the remainder provided by the extreme UV m. We tabulate the best-fit model SED. We use local scaling relations to estimate a star formation rate (SFR) in the range 60−270 M ⊙ /yr from the [C ii] line luminosity and the 158 μ m continuum luminosity. An analysis of the equivalent widths of the [C ii] line in a sample of z > 5.7 quasars suggests that these indicators are promising tools for estimating the SFR in high-redshift quasars in general. At the time observed the black hole was growing in mass more than 100 times faster than the stellar bulge, relative to the mass ratio measured in the local universe, i.e. compared to M BH /M bulge ≃ 1.4 × 10-3 , for ULAS J1120+0641 we measure Ṁ BH /Ṁ bulge ≃ 0.2.
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the Spectral Energy Distribution of the redshift 7 1 quasar ulas j1120 0641
Astronomy and Astrophysics, 2015Co-Authors: R Barnett, S J Warren, Manda Banerji, R G Mcmahon, Paul C Hewett, D Mortlock, Chris Simpson, B P Venemans, Kazuaki OtaAbstract:We present new observations of the highest-redshift quasar known, ULAS J1120+0641, redshift z = 7:084, obtained in the optical, at near-, mid-, and far-infrared wavelengths, and in the sub-mm. We combine these results with published X-ray and radio observations to create the multiwavelength Spectral Energy Distribution (SED), with the goals of measuring the bolometric luminosity Lbol, and quantifying the respective contributions from the AGN and star formation. We find three components are needed to fit the data over the wavelength range 0:12 1000 m: the unobscured quasar accretion disk and broad-line region, a dusty clumpy AGN torus, and a cool 47K modified black body to characterise star formation. Despite the low signal-to-noise ratio of the new long-wavelength data, the normalisation of any dusty torus model is constrained within 40%. We measure a bolometric luminosity Lbol = 2:6 0:6 10 47 erg s 1 = 6:7 1:6 10 13 L , to which the three components contribute 31%; 32%; 3%, respectively, with the remainder provided by the extreme UV 5:7 quasars suggests that these indicators are promising tools for estimating the SFR in high-redshift quasars in general. At the time observed the black hole was growing in mass more than 100 times faster than the stellar bulge, relative to the mass ratio measured in the local universe, i.e. compared to MBH=Mbulge’ 1:4 10 3 , for ULAS J1120+0641 we measure ˙ MBH= ˙ Mbulge’ 0:2.
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the Spectral Energy Distribution of the redshift 7 1 quasar ulas j1120 0641
arXiv: Astrophysics of Galaxies, 2014Co-Authors: R Barnett, S J Warren, Manda Banerji, R G Mcmahon, Paul C Hewett, D Mortlock, Chris Simpson, B P Venemans, Kazuaki OtaAbstract:We present new observations of the highest-redshift quasar known, ULAS J1120+0641, redshift $z=7.084$, obtained in the optical, at near-, mid-, and far-infrared wavelengths, and in the sub-mm. We combine these results with published X-ray and radio observations to create the multiwavelength Spectral Energy Distribution (SED), with the goals of measuring the bolometric luminosity $L_{\rm bol}$, and quantifying the respective contributions from the AGN and star formation. We find three components are needed to fit the data over the wavelength range $0.12-1000\,\mu$m: the unobscured quasar accretion disk and broad-line region, a dusty clumpy AGN torus, and a cool 47K modified black body to characterise star formation. Despite the low signal-to-noise ratio of the new long-wavelength data, the normalisation of any dusty torus model is constrained within $\pm40\%$. We measure a bolometric luminosity $L_{\rm bol}=2.6\pm0.6\times10^{47}\,$erg$\,$s$^{-1}=6.7 \pm 1.6\times10^{13}L_{\odot}$, to which the three components contribute $31\%,32\%,3\%$, respectively, with the remainder provided by the extreme UV $ 5.7$ quasars suggests that these indicators are promising tools for estimating the SFR in high-redshift quasars in general. At the time observed the black hole was growing in mass more than 100 times faster than the stellar bulge, relative to the mass ratio measured in the local universe, i.e. compared to ${M_{\rm BH}}/{M_{\rm bulge}} \simeq 1.4\times10^{-3}$, for ULAS J1120+0641 we measure ${\dot{M}_{\rm BH}}/{\dot{M}_{\rm bulge}} \simeq 0.2$.
R Adam - One of the best experts on this subject based on the ideXlab platform.
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nika 150 ghz polarization observations of the crab nebula and its Spectral Energy Distribution
Astronomy and Astrophysics, 2018Co-Authors: A Ritacco, J F Maciasperez, N Ponthieu, R Adam, Peter A R Ade, Ph Andre, J Aumont, A Beelen, A Benoit, A BideaudAbstract:The Crab nebula is a supernova remnant exhibiting a highly polarized synchrotron radiation at radio and millimeter wavelengths. It is the brightest source in the microwave sky with an extension of 7 by 5 arcminutes and commonly used as a standard candle for any experiment which aims at measuring the polarization of the sky. Though its Spectral Energy Distribution has been well characterized in total intensity, polarization data are still lacking at millimetre wavelengths. We report in this paper high resolution (18 arcsec FWHM) observations of the Crab nebula in total intensity and linear polarization at 150 GHz with the NIKA camera. NIKA, operated at the IRAM 30 m telescope from 2012 to 2015, is a camera made of Lumped Element Kinetic Inductance Detectors (LEKIDs) observing the sky at 150 and 260 GHz. From these observations we are able to reconstruct the spatial Distribution of the polarization degree and angle of the Crab nebula, which is found to be compatible with previous observations at lower and higher frequencies. Averaging across the source and using other existing data sets we find that the Crab nebula polarization angle is consistent with being constant over a wide range of frequencies with a value of -87.7$^\circ$ +- 0.3 in Galactic coordinates. We also present the first estimation of the Crab nebula Spectral Energy Distribution polarized flux in a wide frequency range: 30-353 GHz. Assuming a single power law emission model we find that the polarization Spectral index $\beta_{pol}$ = - 0.347 +- 0.026 is compatible with the intensity Spectral index $\beta$ = - 0.323 +- 0.001.
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nika 150 ghz polarization observations of the crab nebula and its Spectral Energy Distribution
Astronomy and Astrophysics, 2018Co-Authors: A Ritacco, J F Maciasperez, N Ponthieu, R Adam, Peter A R Ade, Ph Andre, J Aumont, A Beelen, A BenoitAbstract:The Crab nebula is a supernova remnant exhibiting a highly polarized synchrotron radiation at radio and millimetre wavelengths. It is the brightest source in the microwave sky with an extension of 7 by 5 arcmin, and is commonly used as a standard candle for any experiment which aims to measure the polarization of the sky. Though its Spectral Energy Distribution has been well characterized in total intensity, polarization data are still lacking at millimetre wavelengths. We report in this paper high resolution observations (18′′ FWHM) of the Crab nebula in total intensity and linear polarization at 150 GHz with the NIKA camera. NIKA, operated at the IRAM 30 m telescope from 2012 to 2015, is a camera made of Lumped Element Kinetic Inductance Detectors (LEKIDs) observing the sky at 150 and 260 GHz. From these observations we are able to reconstruct the spatial Distribution of the polarization degree and angle of the Crab nebula, which is found to be compatible with previous observations at lower and higher frequencies. Averaging across the source and using other existing data sets we find that the Crab nebula polarization angle is consistent with being constant over a wide range of frequencies with a value of − 87.7° ± 0.3 in Galactic coordinates. We also present the first estimation of the Crab nebula Spectral Energy Distribution polarized flux in a wide frequency range: 30–353 GHz. Assuming a single power law emission model we find that the polarization Spectral index βpol = – 0.347 ± 0.026 is compatible with the intensity Spectral index β = – 0.323 ± 0.001.
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planck intermediate results xliii Spectral Energy Distribution of dust in clusters of galaxies
Astronomy and Astrophysics, 2016Co-Authors: R Adam, Peter A R Ade, J Aumont, N Aghanim, M Ashdown, C Baccigalupi, A J Banday, R B Barreiro, N BartoloAbstract:Although infrared (IR) overall dust emission from clusters of galaxies has been statistically detected using data from the Infrared Astronomical Satellite (IRAS), it has not been possible to sample the Spectral Energy Distribution (SED) of this emission over its peak, and thus to break the degeneracy between dust temperature and mass. By complementing the IRAS Spectral coverage with Planck satellite data from 100 to 857 GHz, we provide new constraints on the IR spectrum of thermal dust emission in clusters of galaxies. We achieve this by using a stacking approach for a sample of several hundred objects from the Planck cluster sample; this procedure averages out fluctuations from the IR sky, allowing us to reach a significant detection of the faint cluster contribution. We also use the large frequency range probed by Planck, together with component-separation techniques, to remove the contamination from both cosmic microwave background anisotropies and the thermal Sunyaev-Zeldovich effect (tSZ) signal, which dominate below 353 GHz. By excluding dominant spurious signals or systematic effects, averaged detections are reported at frequencies between 353 and 5000 GHz. We confirm the presence of dust in clusters of galaxies at low and intermediate redshifts, yielding an SED with a shape similar to that of the Milky Way. Planck's beam does not allow us to investigate the detailed spatial Distribution of this emission (e.g., whether it comes from intergalactic dust or simply the dust content of the cluster galaxies), but the radial Distribution of the emission appears to follow that of the stacked SZ signal, and thus the extent of the clusters. The recovered SED allows us to constrain the dust mass responsible for the signal, as well as its temperature. We additionally explore the evolution of the IR emission as a function of cluster mass and redshift.
