Determination of the gas-to-dust ratio in nearby dense clouds using X-ray absorption measurements

Details Determination of the gas-to-dust ratio in nearby dense clouds using X-ray absorption measurements Determination of the gas-to-dust ratio in nearby dense clouds using X-ray absorption measurements

2003-06-23

arxiv.org/abs/astro-ph/0306447v1

Astron.Astrophys.408:581,2003

Astronomy and Astrophysics

Astrophysics

21 Pages including 12 figures. Accepted for publication in Astronomy and Astrophysics

Scientific paper

10.1051/0004-6361:20030942

We present a comparison of the gas and dust properties of the dense interstellar matter in six nearby star-forming regions (d<500 pc): rho Oph, Cha I, R CrA, IC 348, NGC 1333, and Orion. We measure from Chandra and XMM-Newton observations the X-ray absorption toward pre-main sequence stars (PMS) without accretion disks (i.e., Class III sources) to obtain the total hydrogen column density N_{H,X}. For these sources we take from the literature the corresponding dust extinction in the near-infrared, A_J, or when unavailable we derive it from SED fitting using the available DENIS, 2MASS, ISOCAM and other data. We then compare N_{H,X} and A_J for each object, up to unprecedently high extinction. For the rho Oph dark cloud with a relatively large sample of 20 bona-fide Class III sources, we probe the extinction up to A_J <~ 14 (A_V <~ 45), and find a best-fit linear relation N_{H,X}/A_J = 5.6 (+/- 0.4)x10^{21} cm^{-2} mag^{-1}, adopting standard ISM abundances. The other regions reveal a large dispersion in the N_{H,X}/A_J ratio for each source but for lack of adequate IR data these studies remain limited to moderate extinctions (A_J <~ 1.5 or A_V <~5). For rho Oph, the N_{H,X}/A_J ratio is significantly lower (>~2 sigma) than the galactic value, derived using the standard extinction curve (R_V = 3.1). This result is consistent with the recent downwards revision of the metallicity of the Sun and stars in the solar vicinity. We find that the rho Oph dense cloud has the same metallicity than the local ISM when assuming that the galactic gas-to-dust ratio remains unchanged. The difference between galactic and local values of the gas-to-dust ratio can thus be attributed entirely to a difference in metallicity.

Affiliated with

Also associated with

No associations

Rating

Determination of the gas-to-dust ratio in nearby dense clouds using X-ray absorption measurements does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Determination of the gas-to-dust ratio in nearby dense clouds using X-ray absorption measurements, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Determination of the gas-to-dust ratio in nearby dense clouds using X-ray absorption measurements will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-513998