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Gordon K D - One of the best experts on this subject based on the ideXlab platform.

  • Milky Way Mid-Infrared Spitzer Spectroscopic Extinction Curves: Continuum And Silicate Features
    LSU Digital Commons, 2021
    Co-Authors: Gordon K D, Misselt K A, Bouwman J, Clayton G C, Hines D C, Pendleton Y, Rieke G, Smith J D, Whittet D C
    Abstract:

    We measured the mid-infrared (MIR) extinction using Spitzer photometry and spectroscopy (3.6-37 mu m) for a sample of Milky Way sight lines (mostly) having measured ultraviolet extinction curves. We used the pair method to determine the MIR extinction that we then fit with a power law for the continuum and modified Drude profiles for the silicate Features. We derived 16 extinction curves having a range of A(V) (1.8-5.5) and R(V) values (2.4-4.3). Our sample includes two dense sight lines that have 3 mu m Ice Feature detections and weak 2175 angstrom bumps. The average A(lambda)/A(V) diffuse sight-line extinction curve we calculate is lower than most previous literature measurements. This agrees better with literature diffuse dust grain models, though it is somewhat higher. The 10 mu m silicate Feature does not correlate with the 2175 angstrom bump, for the first time providing direct observational confirmation that these two Features arise from different grain populations. The strength of the 10 mu m silicate Feature varies by similar to 2.5 and is not correlated with A(V) or R(V). It is well fit by a modified Drude profile with strong correlations seen between the central wavelength, width, and asymmetry. We do not detect other Features with limits in A(lambda)/A(V) units of 0.0026 (5-10 mu m), 0.004 (10-20 mu m), and 0.008 (20-40 mu m). We find that the standard prescription of estimating R(V) from C x E(K ( s ) - V)/E(B - V) has C = -1.14 and a scatter of similar to 7%. Using the IRAC 5.6 mu m band instead of K ( s ) gives C = -1.03 and the least scatter of similar to 3%

Whittet D.c.b. - One of the best experts on this subject based on the ideXlab platform.

  • Milky Way Mid-Infrared Spitzer Spectroscopic Extinction Curves: Continuum and Silicate Features
    'American Astronomical Society', 2021
    Co-Authors: Gordon K.d., Bouwman J, Pendleton Y, Rieke G, Misselt K.a., Clayton G.c., Decleir M., Hines D.c., Smith J.d.t., Whittet D.c.b.
    Abstract:

    We measured the mid-infrared (MIR) extinction using Spitzer photometry and spectroscopy (3.6-37 μm) for a sample of Milky Way sight lines (mostly) having measured ultraviolet extinction curves. We used the pair method to determine the MIR extinction that we then fit with a power law for the continuum and modified Drude profiles for the silicate Features. We derived 16 extinction curves having a range of A(V) (1.8-5.5) and R(V) values (2.4-4.3). Our sample includes two dense sight lines that have 3 μm Ice Feature detections and weak 2175 Å bumps. The average A(λ)/A(V) diffuse sight-line extinction curve we calculate is lower than most previous literature measurements. This agrees better with literature diffuse dust grain models, though it is somewhat higher. The 10 μm silicate Feature does not correlate with the 2175 Å bump, for the first time providing direct observational confirmation that these two Features arise from different grain populations. The strength of the 10 μm silicate Feature varies by ∼2.5 and is not correlated with A(V) or R(V). It is well fit by a modified Drude profile with strong correlations seen between the central wavelength, width, and asymmetry. We do not detect other Features with limits in A(λ)/A(V) units of 0.0026 (5-10 μm), 0.004 (10-20 μm), and 0.008 (20-40 μm). We find that the standard prescription of estimating R(V) from C E(K s - V)/E(B - V) has C = -1.14 and a scatter of ∼7%. Using the IRAC 5.6 μm band instead of K s gives C = -1.03 and the least scatter of ∼3%. © 2021. The American Astronomical Society. All rights reserved..Immediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu

Whittet D C - One of the best experts on this subject based on the ideXlab platform.

  • Milky Way Mid-Infrared Spitzer Spectroscopic Extinction Curves: Continuum And Silicate Features
    LSU Digital Commons, 2021
    Co-Authors: Gordon K D, Misselt K A, Bouwman J, Clayton G C, Hines D C, Pendleton Y, Rieke G, Smith J D, Whittet D C
    Abstract:

    We measured the mid-infrared (MIR) extinction using Spitzer photometry and spectroscopy (3.6-37 mu m) for a sample of Milky Way sight lines (mostly) having measured ultraviolet extinction curves. We used the pair method to determine the MIR extinction that we then fit with a power law for the continuum and modified Drude profiles for the silicate Features. We derived 16 extinction curves having a range of A(V) (1.8-5.5) and R(V) values (2.4-4.3). Our sample includes two dense sight lines that have 3 mu m Ice Feature detections and weak 2175 angstrom bumps. The average A(lambda)/A(V) diffuse sight-line extinction curve we calculate is lower than most previous literature measurements. This agrees better with literature diffuse dust grain models, though it is somewhat higher. The 10 mu m silicate Feature does not correlate with the 2175 angstrom bump, for the first time providing direct observational confirmation that these two Features arise from different grain populations. The strength of the 10 mu m silicate Feature varies by similar to 2.5 and is not correlated with A(V) or R(V). It is well fit by a modified Drude profile with strong correlations seen between the central wavelength, width, and asymmetry. We do not detect other Features with limits in A(lambda)/A(V) units of 0.0026 (5-10 mu m), 0.004 (10-20 mu m), and 0.008 (20-40 mu m). We find that the standard prescription of estimating R(V) from C x E(K ( s ) - V)/E(B - V) has C = -1.14 and a scatter of similar to 7%. Using the IRAC 5.6 mu m band instead of K ( s ) gives C = -1.03 and the least scatter of similar to 3%

Pendleton Y - One of the best experts on this subject based on the ideXlab platform.

  • Milky Way Mid-Infrared Spitzer Spectroscopic Extinction Curves: Continuum And Silicate Features
    LSU Digital Commons, 2021
    Co-Authors: Gordon K D, Misselt K A, Bouwman J, Clayton G C, Hines D C, Pendleton Y, Rieke G, Smith J D, Whittet D C
    Abstract:

    We measured the mid-infrared (MIR) extinction using Spitzer photometry and spectroscopy (3.6-37 mu m) for a sample of Milky Way sight lines (mostly) having measured ultraviolet extinction curves. We used the pair method to determine the MIR extinction that we then fit with a power law for the continuum and modified Drude profiles for the silicate Features. We derived 16 extinction curves having a range of A(V) (1.8-5.5) and R(V) values (2.4-4.3). Our sample includes two dense sight lines that have 3 mu m Ice Feature detections and weak 2175 angstrom bumps. The average A(lambda)/A(V) diffuse sight-line extinction curve we calculate is lower than most previous literature measurements. This agrees better with literature diffuse dust grain models, though it is somewhat higher. The 10 mu m silicate Feature does not correlate with the 2175 angstrom bump, for the first time providing direct observational confirmation that these two Features arise from different grain populations. The strength of the 10 mu m silicate Feature varies by similar to 2.5 and is not correlated with A(V) or R(V). It is well fit by a modified Drude profile with strong correlations seen between the central wavelength, width, and asymmetry. We do not detect other Features with limits in A(lambda)/A(V) units of 0.0026 (5-10 mu m), 0.004 (10-20 mu m), and 0.008 (20-40 mu m). We find that the standard prescription of estimating R(V) from C x E(K ( s ) - V)/E(B - V) has C = -1.14 and a scatter of similar to 7%. Using the IRAC 5.6 mu m band instead of K ( s ) gives C = -1.03 and the least scatter of similar to 3%

  • Milky Way Mid-Infrared Spitzer Spectroscopic Extinction Curves: Continuum and Silicate Features
    'American Astronomical Society', 2021
    Co-Authors: Gordon K.d., Bouwman J, Pendleton Y, Rieke G, Misselt K.a., Clayton G.c., Decleir M., Hines D.c., Smith J.d.t., Whittet D.c.b.
    Abstract:

    We measured the mid-infrared (MIR) extinction using Spitzer photometry and spectroscopy (3.6-37 μm) for a sample of Milky Way sight lines (mostly) having measured ultraviolet extinction curves. We used the pair method to determine the MIR extinction that we then fit with a power law for the continuum and modified Drude profiles for the silicate Features. We derived 16 extinction curves having a range of A(V) (1.8-5.5) and R(V) values (2.4-4.3). Our sample includes two dense sight lines that have 3 μm Ice Feature detections and weak 2175 Å bumps. The average A(λ)/A(V) diffuse sight-line extinction curve we calculate is lower than most previous literature measurements. This agrees better with literature diffuse dust grain models, though it is somewhat higher. The 10 μm silicate Feature does not correlate with the 2175 Å bump, for the first time providing direct observational confirmation that these two Features arise from different grain populations. The strength of the 10 μm silicate Feature varies by ∼2.5 and is not correlated with A(V) or R(V). It is well fit by a modified Drude profile with strong correlations seen between the central wavelength, width, and asymmetry. We do not detect other Features with limits in A(λ)/A(V) units of 0.0026 (5-10 μm), 0.004 (10-20 μm), and 0.008 (20-40 μm). We find that the standard prescription of estimating R(V) from C E(K s - V)/E(B - V) has C = -1.14 and a scatter of ∼7%. Using the IRAC 5.6 μm band instead of K s gives C = -1.03 and the least scatter of ∼3%. © 2021. The American Astronomical Society. All rights reserved..Immediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu

Bouwman J - One of the best experts on this subject based on the ideXlab platform.

  • Milky Way Mid-Infrared Spitzer Spectroscopic Extinction Curves: Continuum And Silicate Features
    LSU Digital Commons, 2021
    Co-Authors: Gordon K D, Misselt K A, Bouwman J, Clayton G C, Hines D C, Pendleton Y, Rieke G, Smith J D, Whittet D C
    Abstract:

    We measured the mid-infrared (MIR) extinction using Spitzer photometry and spectroscopy (3.6-37 mu m) for a sample of Milky Way sight lines (mostly) having measured ultraviolet extinction curves. We used the pair method to determine the MIR extinction that we then fit with a power law for the continuum and modified Drude profiles for the silicate Features. We derived 16 extinction curves having a range of A(V) (1.8-5.5) and R(V) values (2.4-4.3). Our sample includes two dense sight lines that have 3 mu m Ice Feature detections and weak 2175 angstrom bumps. The average A(lambda)/A(V) diffuse sight-line extinction curve we calculate is lower than most previous literature measurements. This agrees better with literature diffuse dust grain models, though it is somewhat higher. The 10 mu m silicate Feature does not correlate with the 2175 angstrom bump, for the first time providing direct observational confirmation that these two Features arise from different grain populations. The strength of the 10 mu m silicate Feature varies by similar to 2.5 and is not correlated with A(V) or R(V). It is well fit by a modified Drude profile with strong correlations seen between the central wavelength, width, and asymmetry. We do not detect other Features with limits in A(lambda)/A(V) units of 0.0026 (5-10 mu m), 0.004 (10-20 mu m), and 0.008 (20-40 mu m). We find that the standard prescription of estimating R(V) from C x E(K ( s ) - V)/E(B - V) has C = -1.14 and a scatter of similar to 7%. Using the IRAC 5.6 mu m band instead of K ( s ) gives C = -1.03 and the least scatter of similar to 3%

  • Milky Way Mid-Infrared Spitzer Spectroscopic Extinction Curves: Continuum and Silicate Features
    'American Astronomical Society', 2021
    Co-Authors: Gordon K.d., Bouwman J, Pendleton Y, Rieke G, Misselt K.a., Clayton G.c., Decleir M., Hines D.c., Smith J.d.t., Whittet D.c.b.
    Abstract:

    We measured the mid-infrared (MIR) extinction using Spitzer photometry and spectroscopy (3.6-37 μm) for a sample of Milky Way sight lines (mostly) having measured ultraviolet extinction curves. We used the pair method to determine the MIR extinction that we then fit with a power law for the continuum and modified Drude profiles for the silicate Features. We derived 16 extinction curves having a range of A(V) (1.8-5.5) and R(V) values (2.4-4.3). Our sample includes two dense sight lines that have 3 μm Ice Feature detections and weak 2175 Å bumps. The average A(λ)/A(V) diffuse sight-line extinction curve we calculate is lower than most previous literature measurements. This agrees better with literature diffuse dust grain models, though it is somewhat higher. The 10 μm silicate Feature does not correlate with the 2175 Å bump, for the first time providing direct observational confirmation that these two Features arise from different grain populations. The strength of the 10 μm silicate Feature varies by ∼2.5 and is not correlated with A(V) or R(V). It is well fit by a modified Drude profile with strong correlations seen between the central wavelength, width, and asymmetry. We do not detect other Features with limits in A(λ)/A(V) units of 0.0026 (5-10 μm), 0.004 (10-20 μm), and 0.008 (20-40 μm). We find that the standard prescription of estimating R(V) from C E(K s - V)/E(B - V) has C = -1.14 and a scatter of ∼7%. Using the IRAC 5.6 μm band instead of K s gives C = -1.03 and the least scatter of ∼3%. © 2021. The American Astronomical Society. All rights reserved..Immediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu