Evidence for a clumpy, rotating gas disk in a submillimeter galaxy at z = 4

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dc.contributor.authorHodge, J A
dc.contributor.authorCarilli, C L
dc.contributor.authorWalter, F
dc.contributor.authorde Blok, W J G
dc.contributor.authorRiechers, D
dc.contributor.authorDaddi, E
dc.contributor.authorLentati, L
dc.date.accessioned2021-10-08T07:20:38Z
dc.date.available2021-10-08T07:20:38Z
dc.date.issued2012
dc.description.abstractWe present Karl G. Jansky Very Large Array observations of the CO(2-1) emission in the z = 4.05 submillimeter galaxy (SMG) GN20. These high-resolution data allow us to image the molecular gas at 1.3 kpc resolution just 1.6 Gyr after the big bang. The data reveal a clumpy, extended gas reservoir, 14 {+-} 4 kpc in diameter, in unprecedented detail. A dynamical analysis shows that the data are consistent with a rotating disk of total dynamical mass 5.4 {+-} 2.4 Multiplication-Sign 10{sup 11} M {sub Sun }. We use this dynamical mass estimate to constrain the CO-to-H{sub 2} mass conversion factor ({alpha}{sub CO}), finding {alpha}{sub CO} = 1.1 {+-} 0.6 M {sub Sun }(K km s{sup -1} pc{sup 2}){sup -1}. We identify five distinct molecular gas clumps in the disk of GN20 with masses a few percent of the total gas mass, brightness temperatures of 16-31K, and surface densities of >3200-4500 Multiplication-Sign ({alpha}{sub CO}/0.8) M {sub Sun} pc{sup -2}. Virial mass estimates indicate they could be self-gravitating, and we constrain their CO-to-H{sub 2} mass conversion factor to be <0.2-0.7 M {sub Sun }(K km s{sup -1} pc{sup 2}){sup -1}. A multiwavelength comparison demonstrates that the molecular gas is concentrated in a region of the galaxy that is heavily obscured in the rest-frame UV/optical. We investigate the spatially resolved gas excitation and find that the CO(6-5)/CO(2-1) ratio is constant with radius, consistent with star formation occurring over a large portion of the disk. We discuss the implications of our results in the context of different fueling scenarios for SMGs.
dc.identifier.apacitationHodge, J. A., Carilli, C. L., Walter, F., de Blok, W. J. G., Riechers, D., Daddi, E., & Lentati, L. (2012). Evidence for a clumpy, rotating gas disk in a submillimeter galaxy at z = 4. <i>The Astrophysical Journal</i>, 760(1), 11 - 177. http://hdl.handle.net/11427/34970en_ZA
dc.identifier.chicagocitationHodge, J A, C L Carilli, F Walter, W J G de Blok, D Riechers, E Daddi, and L Lentati "Evidence for a clumpy, rotating gas disk in a submillimeter galaxy at z = 4." <i>The Astrophysical Journal</i> 760, 1. (2012): 11 - 177. http://hdl.handle.net/11427/34970en_ZA
dc.identifier.citationHodge, J.A., Carilli, C.L., Walter, F., de Blok, W.J.G., Riechers, D., Daddi, E. & Lentati, L. 2012. Evidence for a clumpy, rotating gas disk in a submillimeter galaxy at z = 4. <i>The Astrophysical Journal.</i> 760(1):11 - 177. http://hdl.handle.net/11427/34970en_ZA
dc.identifier.issn0004-637X
dc.identifier.issn1538-4357
dc.identifier.ris TY - Journal Article AU - Hodge, J A AU - Carilli, C L AU - Walter, F AU - de Blok, W J G AU - Riechers, D AU - Daddi, E AU - Lentati, L AB - We present Karl G. Jansky Very Large Array observations of the CO(2-1) emission in the z = 4.05 submillimeter galaxy (SMG) GN20. These high-resolution data allow us to image the molecular gas at 1.3 kpc resolution just 1.6 Gyr after the big bang. The data reveal a clumpy, extended gas reservoir, 14 {+-} 4 kpc in diameter, in unprecedented detail. A dynamical analysis shows that the data are consistent with a rotating disk of total dynamical mass 5.4 {+-} 2.4 Multiplication-Sign 10{sup 11} M {sub Sun }. We use this dynamical mass estimate to constrain the CO-to-H{sub 2} mass conversion factor ({alpha}{sub CO}), finding {alpha}{sub CO} = 1.1 {+-} 0.6 M {sub Sun }(K km s{sup -1} pc{sup 2}){sup -1}. We identify five distinct molecular gas clumps in the disk of GN20 with masses a few percent of the total gas mass, brightness temperatures of 16-31K, and surface densities of >3200-4500 Multiplication-Sign ({alpha}{sub CO}/0.8) M {sub Sun} pc{sup -2}. Virial mass estimates indicate they could be self-gravitating, and we constrain their CO-to-H{sub 2} mass conversion factor to be <0.2-0.7 M {sub Sun }(K km s{sup -1} pc{sup 2}){sup -1}. A multiwavelength comparison demonstrates that the molecular gas is concentrated in a region of the galaxy that is heavily obscured in the rest-frame UV/optical. We investigate the spatially resolved gas excitation and find that the CO(6-5)/CO(2-1) ratio is constant with radius, consistent with star formation occurring over a large portion of the disk. We discuss the implications of our results in the context of different fueling scenarios for SMGs. DA - 2012 DB - OpenUCT DP - University of Cape Town IS - 1 J1 - The Astrophysical Journal LK - https://open.uct.ac.za PY - 2012 SM - 0004-637X SM - 1538-4357 T1 - Evidence for a clumpy, rotating gas disk in a submillimeter galaxy at z = 4 TI - Evidence for a clumpy, rotating gas disk in a submillimeter galaxy at z = 4 UR - http://hdl.handle.net/11427/34970 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/34970
dc.identifier.vancouvercitationHodge JA, Carilli CL, Walter F, de Blok WJG, Riechers D, Daddi E, et al. Evidence for a clumpy, rotating gas disk in a submillimeter galaxy at z = 4. The Astrophysical Journal. 2012;760(1):11 - 177. http://hdl.handle.net/11427/34970.en_ZA
dc.language.isoeng
dc.publisher.departmentDepartment of Astronomy
dc.publisher.facultyFaculty of Science
dc.sourceThe Astrophysical Journal
dc.source.journalissue1
dc.source.journalvolume760
dc.source.pagination11 - 177
dc.source.urihttps://dx.doi.org/10.1088/0004-637X/760/1/11
dc.subject.otherastrophysics
dc.subject.othercosmology and astronomy
dc.subject.otherastronomy
dc.subject.otherbrightness
dc.subject.othercomparative evaluations
dc.subject.otherconversion
dc.subject.otherexcitation
dc.subject.othergalactic evolution
dc.subject.othergalaxies
dc.subject.otherhydrogen
dc.subject.othermass
dc.subject.otherphoton emission
dc.subject.otherred shift
dc.subject.otherresolution
dc.subject.otherstars
dc.titleEvidence for a clumpy, rotating gas disk in a submillimeter galaxy at z = 4
dc.typeJournal Article
uct.type.publicationResearch
uct.type.resourceJournal Article
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