CO-dark gas and molecular filaments in Milky Way-type galaxies

被引：166

作者：

Smith, Rowan J. ^{[1
]}

Glover, Simon C. O. ^{[1
]}

Clark, Paul C. ^{[1
]}

Klessen, Ralf S. ^{[1
]}

Springel, Volker ^{[2
,3
]}

机构：

[1] Heidelberg Univ, Inst Theoret Astrophys, Zentrum Astron, D-69120 Heidelberg, Germany

[2] Heidelberger Inst Theoret Studien, D-69118 Heidelberg, Germany

[3] Heidelberg Univ, Astron Recheninst, Zentrum Astron, D-69120 Heidelberg, Germany

来源：

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | 2014年 / 441卷 / 02期

基金：

欧洲研究理事会;

关键词：

astrochemistry; hydrodynamics; ISM: clouds; ISM: molecules; galaxies: ISM; INTERSTELLAR-MEDIUM; STAR-FORMATION; DIFFUSE CLOUDS; SOLAR NEIGHBORHOOD; X-FACTOR; CHEMISTRY; PHOTODISSOCIATION; EMISSION; HYDROGEN; H-2;

D O I：

10.1093/mnras/stu616

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We use the moving mesh code arepo coupled to a time-dependent chemical network to investigate molecular gas in simulated spiral galaxies that is not traced by CO emission. We calculate H-2 and CO column densities, and estimate the CO emission and CO-H-2 conversion factor. We find that in conditions akin to those in the local interstellar medium, around 42 per cent of the total molecular mass should be in CO-dark regions, in reasonable agreement with observational estimates. This fraction is almost insensitive to the CO-integrated intensity threshold used to discriminate between CO-bright and CO-dark gas. The CO-dark molecular gas primarily resides in extremely long (> 100 pc) filaments that are stretched between spiral arms by galactic shear. Only the centres of these filaments are bright in CO, suggesting that filamentary molecular clouds observed in the Milky Way may only be small parts of much larger structures. The CO-dark molecular gas mainly exists in a partially molecular phase which accounts for a significant fraction of the total disc mass budget. The dark gas fraction is higher in simulations with higher ambient UV fields or lower surface densities, implying that external galaxies with these conditions might have a greater proportion of dark gas.

引用

页码：1628 / 1645

页数：18

共 77 条

[1] FERMI OBSERVATIONS OF CASSIOPEIA AND CEPHEUS: DIFFUSE GAMMA-RAY EMISSION IN THE OUTER GALAXY [J].

Abdo, A. A. ;

Ackermann, M. ;

Ajello, M. ;

Baldini, L. ;

Ballet, J. ;

Barbiellini, G. ;

Bastieri, D. ;

Baughman, B. M. ;

Bechtol, K. ;

Bellazzini, R. ;

Berenji, B. ;

Bloom, E. D. ;

Bonamente, E. ;

Borgland, A. W. ;

Bregeon, J. ;

Brez, A. ;

Brigida, M. ;

Bruel, P. ;

Burnett, T. H. ;

Buson, S. ;

Caliandro, G. A. ;

Cameron, R. A. ;

Caraveo, P. A. ;

Casandjian, J. M. ;

Cecchi, C. ;

Celik, Oe. ;

Chekhtman, A. ;

Cheung, C. C. ;

Chiang, J. ;

Ciprini, S. ;

Claus, R. ;

Cohen-Tanugi, J. ;

Cominsky, L. R. ;

Conrad, J. ;

Dermer, C. D. ;

de Palma, F. ;

Digel, S. W. ;

do Couto e Silva, E. ;

Drell, P. S. ;

Dubois, R. ;

Dumora, D. ;

Farnier, C. ;

Favuzzi, C. ;

Fegan, S. J. ;

Focke, W. B. ;

Fortin, P. ;

Frailis, M. ;

Fukazawa, Y. ;

Funk, S. ;

Fusco, P. .

ASTROPHYSICAL JOURNAL, 2010, 710 (01) :133-149

[2]

Adams D., 1979, The hitchhiker's guide to the galaxy

[3] Planck early results. XIX. All-sky temperature and dust optical depth from Planck and IRAS. Constraints on the "dark gas" in our Galaxy [J].

Ade, P. A. R. ;

Aghanim, N. ;

Arnaud, M. ;

Ashdown, M. ;

Aumont, J. ;

Baccigalupi, C. ;

Balbi, A. ;

Banday, A. J. ;

Barreiro, R. B. ;

Bartlett, J. G. ;

Battaner, E. ;

Benabed, K. ;

Benoit, A. ;

Bernard, J. -P. ;

Bersanelli, M. ;

Bhatia, R. ;

Bock, J. J. ;

Bonaldi, A. ;

Bond, J. R. ;

Borrill, J. ;

Bouchet, F. R. ;

Boulanger, F. ;

Bucher, M. ;

Burigana, C. ;

Cabella, P. ;

Cardoso, J. -F. ;

Catalano, A. ;

Cayon, L. ;

Challinor, A. ;

Chamballu, A. ;

Chiang, L. -Y ;

Chiang, C. ;

Christensen, P. R. ;

Clements, D. L. ;

Colombi, S. ;

Couchot, F. ;

Coulais, A. ;

Crill, B. P. ;

Cuttaia, F. ;

Dame, T. M. ;

Danese, L. ;

Davies, R. D. ;

Davis, R. J. ;

de Bernardis, P. ;

de Gasperis, G. ;

de Rosa, A. ;

de Zotti, G. ;

Delabrouille, J. ;

Delouis, J. -M. ;

Desert, F. -X. .

ASTRONOMY & ASTROPHYSICS, 2011, 536

[4] FAINT EXTENDED OH EMISSION FROM THE LOCAL INTERSTELLAR MEDIUM IN THE DIRECTION l ≈ 108°, b ≈ 5° [J].

Allen, Ronald J. ;

Ivette Rodriguez, Monica ;

Black, John H. ;

Booth, Roy S. .

ASTRONOMICAL JOURNAL, 2012, 143 (04)

[5]

[Anonymous], P CSEE

[6] Six myths on the virial theorem for interstellar clouds [J].

Ballesteros-Paredes, Javier .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2006, 372 (01) :443-449

[7] Subsonic turbulence in smoothed particle hydrodynamics and moving-mesh simulations [J].

Bauer, Andreas ;

Springel, Volker .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2012, 423 (03) :2558-2578

[8] Cold dark clouds: The initial conditions for star formation [J].

Bergin, Edwin A. ;

Tafalla, Mario .

ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS, 2007, 45 :339-396

[9]

Binney J., 1987, GALACTIC DYNAMICS

[10] The CO-to-H2 Conversion Factor [J].

Bolatto, Alberto D. ;

Wolfire, Mark ;

Leroy, Adam K. .

ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS, VOL 51, 2013, 51 :207-268

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