%0 Generic %1 keenan2017where %A Keenan, Ryan P. %A Oey, M. S. %A Jaskot, Anne E. %A James, Bethan L. %D 2017 %K Haro11 Lyman continuum %T Haro 11: Where is the Lyman continuum source? %U http://arxiv.org/abs/1704.01702 %X Identifying the mechanism by which high energy Lyman continuum (LyC) photons escaped from early galaxies is one of the most pressing questions in cosmic evolution. Haro 11 is the best known local LyC leaking galaxy, providing an important opportunity to test our understanding of how LyC escape occurs. The observed LyC emission in this galaxy presumably originates from one of the three bright, photoionizing knots known as A, B, and C. It is known that Knot C has strong Lyman alpha emission, and Knot B hosts an unusually bright ULX which may be a low luminosity AGN. To clarify the LyC source, we carry out ionization-parameter mapping (IPM) by obtaining narrow-band imaging from the Hubble Space Telescope WFC3 and ACS cameras to construct spatially resolved ratio maps of OIII/OII emission from the galaxy. IPM traces the ionization structure of the interstellar medium and allows us to identify optically thin regions. To optimize the continuum subtraction, we describe a new method for determining the best continuum scale factor derived from the mode of the pixel histogram. We find no conclusive evidence of LyC escape from Knots B or C, but instead, we identify a high-ionization region extending over at least 1 kpc from Knot A. Knot A shows evidence of an extremely young age ($1$ Myr), perhaps containing very massive stars ($>100$ M$_ødot$). It is weak in Lyman alpha, so if it is confirmed as the LyC source, our results imply that LyC emission may be independent of Lyman alpha emission.

@misc{keenan2017where, abstract = {Identifying the mechanism by which high energy Lyman continuum (LyC) photons escaped from early galaxies is one of the most pressing questions in cosmic evolution. Haro 11 is the best known local LyC leaking galaxy, providing an important opportunity to test our understanding of how LyC escape occurs. The observed LyC emission in this galaxy presumably originates from one of the three bright, photoionizing knots known as A, B, and C. It is known that Knot C has strong Lyman alpha emission, and Knot B hosts an unusually bright ULX which may be a low luminosity AGN. To clarify the LyC source, we carry out ionization-parameter mapping (IPM) by obtaining narrow-band imaging from the Hubble Space Telescope WFC3 and ACS cameras to construct spatially resolved ratio maps of [OIII]/[OII] emission from the galaxy. IPM traces the ionization structure of the interstellar medium and allows us to identify optically thin regions. To optimize the continuum subtraction, we describe a new method for determining the best continuum scale factor derived from the mode of the pixel histogram. We find no conclusive evidence of LyC escape from Knots B or C, but instead, we identify a high-ionization region extending over at least 1 kpc from Knot A. Knot A shows evidence of an extremely young age ($\lesssim 1$ Myr), perhaps containing very massive stars ($>100$ M$_\odot$). It is weak in Lyman alpha, so if it is confirmed as the LyC source, our results imply that LyC emission may be independent of Lyman alpha emission.}, added-at = {2017-04-07T10:20:19.000+0200}, author = {Keenan, Ryan P. and Oey, M. S. and Jaskot, Anne E. and James, Bethan L.}, biburl = {https://www.bibsonomy.org/bibtex/2a50eefbdb7d186303b72c6ab398d835e/miki}, description = {[1704.01702] Haro 11: Where is the Lyman continuum source?}, interhash = {2755f0438059c8bfe528ea38130bddba}, intrahash = {a50eefbdb7d186303b72c6ab398d835e}, keywords = {Haro11 Lyman continuum}, note = {cite arxiv:1704.01702Comment: 10 pages, 6 Figures, Submitted to ApJ}, timestamp = {2017-04-07T10:20:19.000+0200}, title = {Haro 11: Where is the Lyman continuum source?}, url = {http://arxiv.org/abs/1704.01702}, year = 2017 }