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Andromeda's Dust: Maps of Dust and Starlight Parameters in M31
Reference: Draine, B.T., Aniano, G., Krause, O., et al. (2014): Astrophysical
Journal, 780, 172.
Spitzer (IRAC, MIPS) and Herschel (PACS, SPIRE) observations of the M31 galaxy have been used to constrain
models for the dust in M31. The methodology is described in Draine, Aniano, Krause et al. (2014).
Maps of the dust surface density (Sigma_Mdust), PAH abundance parameter (q_PAH), mean
starlight heating rate (Ubar), and other properties of the starlight intensity
distribution (U_min, gamma, alpha) are obtained. Note that (as described in the
paper) the derived model parameters become unreliable at large galactocentric radii.
The dust surface density can be reliably measured in individual pixels out to about
18 kpc, but beyond that it is necessary to average over many pixels.
The following gzipped FITS files are available. If you use them in your
research, please cite the paper describing the observations and model-fitting.
Model maps at MIPS 160 resolution (PSF FWHM = 39"; 18" x 18" pixels):
M31_M160_111_SSS_111_All_SurfBr_Mdust.fits.gz: Sigma_Mdust (Msol/kpc^2)
M31_M160_111_SSS_111_All_SurfBr_Mdust_unc.fits.gz: uncertainty in Sigma_Mdust
M31_M160_111_SSS_111_All_qpah.fits.gz: q_PAH
M31_M160_111_SSS_111_All_qpah_unc.fits.gz: uncertainty in q_PAH
M31_M160_111_SSS_111_All_SurfBr_Ldust.fits.gz: Sigma_Ldust (Lsol/kpc^2)
M31_M160_111_SSS_111_All_SurfBr_Ldust_unc.fits.gz: uncertainty in Sigma_Ldust
M31_M160_111_SSS_111_All_U_bar.fits.gz: Ubar
M31_M160_111_SSS_111_All_U_bar_unc.fits.gz: uncertainty in Ubar
M31_M160_111_SSS_111_All_U_min.fits.gz: U_min
M31_M160_111_SSS_111_All_U_min_unc.fits.gz: uncertainty in U_min
M31_M160_111_SSS_111_All_alpha.fits.gz: starlight heating parameter alpha
M31_M160_111_SSS_111_All_alpha_unc.fits.gz: uncertainty in starlight heating parameter alpha
M31_M160_111_SSS_111_All_gamma_unc.fits.gz: starlight heating parameter gamma
M31_M160_111_SSS_111_All_gamma_unc.fits.gz: uncertainty in starlight heating parameter gamma
Model maps at SPIRE 350 resolution (PSF FWHM = 24.9"; 10" x 10" pixels):
M31_S350_110_SSS_110_All_SurfBr_Mdust.fits.gz: Sigma_Mdust (Msol/kpc^2)
M31_S350_110_SSS_110_All_SurfBr_Mdust_unc.fits.gz: uncertainty in Sigma_Mdust
M31_S350_110_SSS_110_All_qpah_unc.fits.gz: q_PAH
M31_S350_110_SSS_110_All_qpah_unc.fits.gz: uncertainty in q_PAH
M31_S350_110_SSS_110_All_SurfBr_Ldust.fits.gz: Sigma_Ldust (Lsol/kpc^2)
M31_S350_110_SSS_110_All_SurfBr_Ldust_unc.fits.gz: uncertainty in Sigma_Ldust
M31_S350_110_SSS_110_All_U_bar.fits.gz: Ubar
M31_S350_110_SSS_110_All_U_bar_unc.fits.gz: uncertainty in Ubar
M31_S350_110_SSS_110_All_U_min.fits.gz: U_min
M31_S350_110_SSS_110_All_U_min_unc.fits.gz: uncertainty in U_min
M31_S350_110_SSS_110_All_alpha.fits.gz: starlight heating parameter alpha
M31_S350_110_SSS_110_All_alpha_unc.fits.gz: uncertainty in starlight heating parameter alpha
M31_S350_110_SSS_110_All_gamma_unc.fits.gz: starlight heating parameter gamma
M31_S350_110_SSS_110_All_gamma_unc.fits.gz: uncertainty in starlight heating parameter gamma
Gas Maps (18" x18" pixels).
If you use these maps, please cite the original source: Braun et al. (2009) for the 21 cm data,
and Nieten et al. (2006) for the CO 1-0 data.
M31_Original_Data_Gas_02.fits.gz: N(HI)/2.247e15 cm-2 (Braun et al 2009)
M31_Original_Data_Gas_02_unc.fits.gz: uncertainty in N(HI)/2.247e15 cm-2 (Braun et al 2009)
M31_Original_Data_Gas_03.fits.gz : I(CO 1-0)/2.475e-7 K km s-1 (Nieten et al 2006)
M31_Original_Data_Gas_03_unc.fits.gz: uncertainty in I(CO 1-0)/2.475e-7 K km s-1 (Nieten et al 2006)
If you encounter difficulties downloading any of these files, please send email to draine at astro.princeton.edu