2005A&A...436..397M


C.D.S. - SIMBAD4 rel 1.7 - 2020.09.18CEST11:15:22

2005A&A...436..397M - Astronomy and Astrophysics, volume 436, 397-409 (2005/6-3)

Diagnostics of irradiated gas in galaxy nuclei. I. A far-ultraviolet and X-ray dominated region code.

MEIJERINK R. and SPAANS M.

Abstract (from CDS):

We present a far-ultraviolet (PDR) and an X-ray dominated region (XDR) code. We include and discuss thermal and chemical processes that pertain to irradiated gas. An elaborate chemical network is used and a careful treatment of PAHs and H2 formation, destruction and excitation is included. For both codes we calculate four depth-dependent models for different densities and radiation fields, relevant to conditions in starburst galaxies and active galactic nuclei. A detailed comparison between PDR and XDR physics is made for total gas column densities between ∼1020 and ∼1025cm–2. We show cumulative line intensities for a number of fine-structure lines (e.g., [CII], [OI], [CI], [SiII], [FeII]), as well as cumulative column densities and column density ratios for a number of species (e.g., CO/H2, CO/C, HCO+/HCN, HNC/HCN). The comparison between the results for the PDRs and XDRs shows that column density ratios are almost constant up to NH=1022cm–2 for XDRs, unlike those in PDRs. For example, CO/C in PDRs changes over four orders of magnitude from the edge to N_ H_=1022cm–2. The CO/C and CO/H2 ratios are lower in XDRs at low column densities and rise at NH>1023cm–2. At most column densities NH>1021.5cm–2, HNC/HCN ratios are lower in XDRs too, but they show a more moderate increase at higher NH.

Abstract Copyright:

Journal keyword(s): astrochemistry - galaxies: starburst - galaxies: active

Simbad objects: 2

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Number of rows : 2

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 NGC 253 SyG 00 47 33.134 -25 17 19.68   8.03   6.94 8.1 ~ 2945 2
2 M 77 GiP 02 42 40.771 -00 00 47.84 9.70 9.61 8.87 10.1 9.9 ~ 4109 2

    Equat.    Gal    SGal    Ecl

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2020.09.18-11:15:22

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