CLASSY VII Lyα Profiles: The Structure and Kinematics of Neutral Gas and Implications for LyC Escape in Reionization-era Analogs

被引：20

作者：

Hu, Weida ^{[1
]}

Martin, Crystal L. ^{[1
]}

Gronke, Max ^{[2
]}

Gazagnes, Simon ^{[3
]}

Hayes, Matthew ^{[4
,5
]}

Chisholm, John ^{[3
]}

Heckman, Timothy ^{[6
]}

Mingozzi, Matilde ^{[7
]}

Roy, Namrata ^{[6
]}

Senchyna, Peter ^{[8
]}

Xu, Xinfeng ^{[6
]}

Berg, Danielle A. ^{[3
]}

James, Bethan L. ^{[9
]}

Stark, Daniel P. ^{[10
]}

Arellano-Cordova, Karla Z. ^{[3
]}

Henry, Alaina ^{[6
,7
]}

Jaskot, Anne E. ^{[11
]}

Kumari, Nimisha ^{[9
]}

Parker, Kaelee S. ^{[3
]}

Scarlata, Claudia ^{[12
]}

Wofford, Aida ^{[13
]}

Amorin, Ricardo O. ^{[14
,15
]}

Leonhardes-Barboza, Naunet ^{[16
]}

Brinchmann, Jarle ^{[17
]}

Carr, Cody ^{[12
]}

Aloisi, Alessandra ^{[7
]}

机构：

[1] Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA

[2] Max Planck Inst Astrophys, Karl Schwarzschild Str 1, D-85741 Garching, Germany

[3] Univ Texas Austin, Dept Astron, 2515 Speedway,Stop C1400, Austin, TX 78712 USA

[4] Stockholm Univ, Dept Astron, SE-10691 Stockholm, Sweden

[5] AlbaNova Univ Ctr, Oskar Klein Ctr Cosmoparticle Phys, SE-10691 Stockholm, Sweden

[6] Johns Hopkins Univ, Ctr Astrophys Sci, Dept Phys & Astron, Baltimore, MD 21218 USA

[7] Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA

[8] Carnegie Observ, 813 Santa Barbara St, Pasadena, CA 91101 USA

[9] Space Telescope Sci Inst, AURA ESA, 3700 San Martin Dr, Baltimore, MD 21218 USA

[10] Univ Arizona, Steward Observ, 933 N Cherry Ave, Tucson, AZ 85721 USA

[11] Williams Coll, Dept Astron, Williams Town, MA 01267 USA

[12] Univ Minnesota, Minnesota Inst Astrophys, 116 Church St SE, Minneapolis, MN 55455 USA

[13] Univ Nacl Autonoma Mexico, Unidad Acad Ensenada, Inst Astron, Km 103 Carr Tijuana Ensenada, Ensenada 22860, Mexico

[14] Univ La Serena, Inst Invest Multidisciplinar Ciencia & Tecnol, Raul Bitran 1305, La Serena 2204000, Chile

[15] Univ La Serena, Dept Astron, Ave Juan Cisternas 1200 Norte, La Serena 1720236, Chile

[16] Wellesley Coll, 106 Cent St, Wellesley, MA 02481 USA

[17] Univ Porto, Inst Astrofis & Ciencias Espaco, CAUP, Rua Estrelas, P-4150762 Porto, Portugal

来源：

ASTROPHYSICAL JOURNAL | 2023年 / 956卷 / 01期

关键词：

STAR-FORMING GALAXIES; LYMAN-ALPHA; RADIATIVE-TRANSFER; IONIZING PHOTONS; EMISSION-LINE; COSMIC REIONIZATION; INTERSTELLAR-MEDIUM; STELLAR POPULATION; LOW-MASS; DUST;

D O I：

10.3847/1538-4357/aceefd

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Ly alpha line profiles are a powerful probe of interstellar medium (ISM) structure, outflow speed, and Lyman-continuum escape fraction. In this paper, we present the Ly alpha line profiles of the Cosmic Origins Spectrograph (COS) Legacy Archive Spectroscopic SurveY, a sample rich in spectroscopic analogs of reionization-era galaxies. A large fraction of the spectra show a complex profile, consisting of a double-peaked Ly alpha emission profile in the bottom of a damped, Ly alpha absorption trough. Such profiles reveal an inhomogeneous ISM. We successfully fit the damped Ly alpha absorption and the Ly alpha emission profiles separately, but with complementary covering factors, a surprising result because this approach requires no Ly alpha exchange between high-N-H I and low-N-H I paths. The combined distribution of column densities is qualitatively similar to the bimodal distributions observed in numerical simulations. We find an inverse relation between Ly alpha peak separation and the [O III]/[O II] flux ratio, confirming that the covering fraction of Lyman-continuum-thin sightlines increases as the Ly alpha peak separation decreases. We combine measurements of Ly alpha peak separation and Ly alpha red peak asymmetry in a diagnostic diagram, which identifies six Lyman-continuum leakers in the COS Legacy Archive Spectrocopy SurveY (CLASSY) sample. We find a strong correlation between the Ly alpha trough velocity and the outflow velocity measured from interstellar absorption lines. We argue that greater vignetting of the blueshifted Ly alpha peak, relative to the redshifted peak, is the source of the well-known discrepancy between shell-model parameters and directly measured outflow properties. The CLASSY sample illustrates how scattering of Ly alpha photons outside the spectroscopic aperture reshapes Ly alpha profiles because the distances to these compact starbursts span a large range.

引用

页数：28

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