Updated extraction of the APOGEE 1.5273 {mu}m diffuse interstellar band: a Planck view on the carrier depletion in dense cores. (arXiv:1903.11707v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Elyajouri_M/0/1/0/all/0/1">Meriem Elyajouri</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lallement_R/0/1/0/all/0/1">Rosine Lallement</a>
The latest SDSS/APOGEE data release DR14 has provided an increased number of
stellar spectra in the H band and associated stellar models using an innovative
algorithm known as The Cannon. We took advantage of these novelties to extract
the 15 273 {AA} near-infrared DIB and to study its link with dust extinction
and emission. We modified our automated fitting methods dedicated to hot stars
and used in earlier studies with some adaptations motivated by the change from
early- or intermediate-type stars to red giants. A new method has also been
developed to quantify the upper limits on DIB strengths. We compared our DIB
measurements with the stellar extinctions Av from the Starhorse database. We
then compared the resulting DIB-extinction ratio with the dust optical depth
derived from Planck data, globally and also separately for nearby off-Plane
cloud complexes. Our analysis has led to the production of a catalog containing
124 064 new measurements of the 15 273 {AA} DIB, allowing us to revisit the
correlation between DIB strength and dust reddening. The new data reveal
clearly that the sky-averaged 15 273 {AA} DIB strength is linearly correlated
with Av over two orders as reported by earlier studies but leveling-off with
respect to extinction for highly reddened lines-of-sight behind dense clouds.
The comparison with Planck individual optical depths reveals in a conspicuous
way this DIB depletion in the dense cores and shows it applies to all off-Plane
dense clouds. APOGEE measurements confirm the ubiquity of the 15 273 {AA} DIB
carrier decrease with respect to dust grains in dense cloud cores, in a manner
that can be empirically related to the dust optical depth reached in the cloud.
The latest SDSS/APOGEE data release DR14 has provided an increased number of
stellar spectra in the H band and associated stellar models using an innovative
algorithm known as The Cannon. We took advantage of these novelties to extract
the 15 273 {AA} near-infrared DIB and to study its link with dust extinction
and emission. We modified our automated fitting methods dedicated to hot stars
and used in earlier studies with some adaptations motivated by the change from
early- or intermediate-type stars to red giants. A new method has also been
developed to quantify the upper limits on DIB strengths. We compared our DIB
measurements with the stellar extinctions Av from the Starhorse database. We
then compared the resulting DIB-extinction ratio with the dust optical depth
derived from Planck data, globally and also separately for nearby off-Plane
cloud complexes. Our analysis has led to the production of a catalog containing
124 064 new measurements of the 15 273 {AA} DIB, allowing us to revisit the
correlation between DIB strength and dust reddening. The new data reveal
clearly that the sky-averaged 15 273 {AA} DIB strength is linearly correlated
with Av over two orders as reported by earlier studies but leveling-off with
respect to extinction for highly reddened lines-of-sight behind dense clouds.
The comparison with Planck individual optical depths reveals in a conspicuous
way this DIB depletion in the dense cores and shows it applies to all off-Plane
dense clouds. APOGEE measurements confirm the ubiquity of the 15 273 {AA} DIB
carrier decrease with respect to dust grains in dense cloud cores, in a manner
that can be empirically related to the dust optical depth reached in the cloud.
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