The Source of Leaking Ionizing Photons from Haro11: Clues from HST/COS Spectroscopy of Knots A, B, and C*
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The Source of Leaking Ionizing Photons from Haro11 : Clues from HST/COS Spectroscopy of Knots A, B, and C*. / Ostlin, Goran; Rivera-Thorsen, T. Emil; Menacho, Veronica; Hayes, Matthew; Runnholm, Axel; Micheva, Genoveva; Oey, M. S.; Adamo, Angela; Bik, Arjan; Cannon, John M.; Gronke, Max; Kunth, Daniel; Laursen, Peter; Mas-Hesse, J. Miguel; Melinder, Jens; Messa, Matteo; Sirressi, Mattia; Smith, Linda.
I: Astrophysical Journal, Bind 912, Nr. 2, 155, 18.05.2021.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - The Source of Leaking Ionizing Photons from Haro11
T2 - Clues from HST/COS Spectroscopy of Knots A, B, and C*
AU - Ostlin, Goran
AU - Rivera-Thorsen, T. Emil
AU - Menacho, Veronica
AU - Hayes, Matthew
AU - Runnholm, Axel
AU - Micheva, Genoveva
AU - Oey, M. S.
AU - Adamo, Angela
AU - Bik, Arjan
AU - Cannon, John M.
AU - Gronke, Max
AU - Kunth, Daniel
AU - Laursen, Peter
AU - Mas-Hesse, J. Miguel
AU - Melinder, Jens
AU - Messa, Matteo
AU - Sirressi, Mattia
AU - Smith, Linda
PY - 2021/5/18
Y1 - 2021/5/18
N2 - Understanding the escape of ionizing (Lyman continuum) photons from galaxies is vital for determining how galaxies contributed to reionization in the early universe. While directly detecting the Lyman continuum from high-redshift galaxies is impossible due to the intergalactic medium, low-redshift galaxies in principle offer this possibility but require observations from space. The first local galaxy for which Lyman continuum escape was found is Haro 11, a luminous blue compact galaxy at z = 0.02, where observations with the FUSE satellite revealed an escape fraction of 3.3%. However, the FUSE aperture covers the entire galaxy, and it is not clear from where the Lyman continuum is leaking out. Here we utilize Hubble Space Telescope/Cosmic Origins Spectrograph spectroscopy in the wavelength range 1100-1700 angstrom of the three knots (A, B, and C) of Haro 11 to study the presence of Ly alpha emission and the properties of intervening gas. We find that all knots have bright Ly alpha emission. UV absorption lines, originating in the neutral interstellar medium, as well as lines probing the ionized medium, are seen extending to blueshifted velocities of 500 km s(-1) in all three knots, demonstrating the presence of an outflowing multiphase medium. We find that knots A and B have large covering fractions of neutral gas, making LyC escape along these sightlines improbable, while knot C has a much lower covering fraction (less than or similar to 50%). Knot C also has the the highest Ly alpha escape fraction, and we conclude that it is the most likely source of the escaping Lyman continuum detected in Haro 11.
AB - Understanding the escape of ionizing (Lyman continuum) photons from galaxies is vital for determining how galaxies contributed to reionization in the early universe. While directly detecting the Lyman continuum from high-redshift galaxies is impossible due to the intergalactic medium, low-redshift galaxies in principle offer this possibility but require observations from space. The first local galaxy for which Lyman continuum escape was found is Haro 11, a luminous blue compact galaxy at z = 0.02, where observations with the FUSE satellite revealed an escape fraction of 3.3%. However, the FUSE aperture covers the entire galaxy, and it is not clear from where the Lyman continuum is leaking out. Here we utilize Hubble Space Telescope/Cosmic Origins Spectrograph spectroscopy in the wavelength range 1100-1700 angstrom of the three knots (A, B, and C) of Haro 11 to study the presence of Ly alpha emission and the properties of intervening gas. We find that all knots have bright Ly alpha emission. UV absorption lines, originating in the neutral interstellar medium, as well as lines probing the ionized medium, are seen extending to blueshifted velocities of 500 km s(-1) in all three knots, demonstrating the presence of an outflowing multiphase medium. We find that knots A and B have large covering fractions of neutral gas, making LyC escape along these sightlines improbable, while knot C has a much lower covering fraction (less than or similar to 50%). Knot C also has the the highest Ly alpha escape fraction, and we conclude that it is the most likely source of the escaping Lyman continuum detected in Haro 11.
KW - LYMAN CONTINUUM ESCAPE
KW - HUBBLE-SPACE-TELESCOPE
KW - LOCAL STARBURST GALAXIES
KW - BLUE COMPACT GALAXIES
KW - STAR-FORMING GALAXIES
KW - LY-ALPHA ESCAPE
KW - H-II REGIONS
KW - GALACTIC OUTFLOWS
KW - YOUNG STARBURST
KW - OPTICAL DEPTH
U2 - 10.3847/1538-4357/abf1e8
DO - 10.3847/1538-4357/abf1e8
M3 - Journal article
VL - 912
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 155
ER -
ID: 270621292