2014A&A...567A..91G


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.11CEST19:54:51

2014A&A...567A..91G - Astronomy and Astrophysics, volume 567A, 91-91 (2014/7-1)

Modeling the H2O submillimeter emission in extragalactic sources.

GONZALEZ-ALFONSO E., FISCHER J., AALTO S. and FALSTAD N.

Abstract (from CDS):

Recent observational studies have shown that H2O emission at (rest) submillimeter wavelengths is ubiquitous in infrared galaxies, both in the local and in the early Universe, suggestive of far-infrared pumping of H2O by dust in warm regions. In this work, models are presented that show that (i) the highest-lying H2O lines (Eupper>400K) are formed in very warm (Tdust>90K) regions and require high H2O columns (NH2O>3x1017cm–2), while lower lying lines can be efficiently excited with Tdust∼45-75K and NH2O~(0.5-2)x1017cm–2; (ii) significant collisional excitation of the lowest lying (Eupper<200K) levels, which enhances the overall LH2O-LIR ratios, is identified in sources where the ground-state para-H2O 111000 line is detected in emission; (iii) the H2O-to-infrared (8-1000µm) luminosity ratio is expected to decrease with increasing Tdust for all lines with Eupper≲300K, as has recently been reported in a sample of LIRGs, but increases with Tdust for the highest lying H2O lines (Eupper>400K); (iv) we find theoretical upper limits for LH2O/LIR in warm environments, owing to H2O line saturation; (v) individual models are presented for two very different prototypical galaxies, the Seyfert 2 galaxy NGC 1068 and the nearest ultraluminous infrared galaxy Arp 220, showing that the excited submillimeter H2O emission is dominated by far-infrared pumping in both cases; (vi) the LH2O-LIR correlation previously reported in observational studies indicates depletion or exhaustion time scales, tdepgasSFR, of ≲12Myr for star-forming sources where lines up to Eupper=300K are detected, in agreement with the values previously found for (U)LIRGs from HCN millimeter emission. We conclude that the submillimeter H2O line emission other than the para-H2O 111000 transition is pumped primarily by far-infrared radiation, though some collisional pumping may contribute to the low-lying para-H2O 202111 line, and that collisional pumping of the para-111 and ortho-212 levels enhances the radiative pumping of the higher lying levels.

Abstract Copyright:

Journal keyword(s): line: formation - galaxies: ISM - infrared: galaxies - submillimeter: galaxies

Simbad objects: 10

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Number of rows : 10

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 M 77 GiP 02 42 40.771 -00 00 47.84 9.70 9.61 8.87 10.1 9.9 ~ 4093 2
2 SPT-S J053816-5030.8 G 05 38 16.830 -50 30 52.00           ~ 22 1
3 QSO J0831+5245 QSO 08 31 41.7095363198 +52 45 17.620340544   19.2   14.5 13.9 ~ 488 1
4 M 82 IG 09 55 52.430 +69 40 46.93 9.61 9.30 8.41     ~ 5336 6
5 NGC 4355 Sy2 12 26 54.628 -00 52 39.51   14.21 13.37     ~ 405 2
6 Mrk 231 Sy1 12 56 14.2340989340 +56 52 25.238555193   14.68 13.84     ~ 1781 3
7 IC 4553 SyG 15 34 57.22396 +23 30 11.6084   14.76 13.88     ~ 2683 4
8 NGC 6240 Sy2 16 52 58.861 +02 24 03.55   14.31 13.37     ~ 1481 2
9 NAME HFLS 3 G 17 06 47.8 +58 46 23           ~ 97 0
10 NAME Stephan's Quintet CGG 22 35 57.5 +33 57 36           ~ 375 1

    Equat.    Gal    SGal    Ecl

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2020.07.11-19:54:51

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