The HDUV Survey: A Revised Assessment of the Relationship between UV Slope and Dust Attenuation for High-Redshift Galaxies. Reddy, N. A., Oesch, P. A., Bouwens, R. J., Montes, M., Illingworth, G. D., Steidel, C. C., van Dokkum, P. G., Atek, H., Carollo, M. C., Cibinel, A., Holden, B., Labbe, I., Magee, D., Morselli, L., Nelson, E. J., & Wilkins, S. ArXiv e-prints, 1705:arXiv:1705.09302, May, 2017.
The HDUV Survey: A Revised Assessment of the Relationship between UV Slope and Dust Attenuation for High-Redshift Galaxies [link]Paper  abstract   bibtex   
We use a newly assembled large sample of 3,545 star-forming galaxies with secure spectroscopic, grism, and photometric redshifts at z=1.5-2.5 to constrain the relationship between UV slope (beta) and dust attenuation (L(IR)/L(UV)=IRX). Our sample benefits from the combination of deep Hubble WFC3/UVIS photometry from the Hubble Deep UV (HDUV) Legacy survey and existing photometric data compiled in the 3D-HST survey, and extends the range of UV luminosity and beta probed in previous UV-selected samples. IRX is measured using stacks of deep Herschel/PACS 100 and 160 micron data, and the results are compared with predictions of the IRX-beta relation for different assumptions of the stellar population model and obscuration curve. We find that z=1.5-2.5 galaxies have an IRX-beta relation that is consistent with the predictions for an SMC extinction curve if we invoke sub-solar metallicity models that are currently favored for high-redshift galaxies, while the commonly assumed starburst attenuation curve over-predicts the IRX at a given beta by a factor of \textasciitilde3. The IRX of high-mass (M*\textgreater10\textasciicircum9.75 Msun) galaxies is a factor of \textgreater4 larger than that of low-mass galaxies, lending support for the use of stellar mass as a proxy for attenuation. The commonly observed trend of fainter galaxies having bluer beta may simply reflect bluer intrinsic UV slopes for such galaxies, rather than lower obscurations. The IRX-beta for young/low-mass galaxies implies a dust curve that is steeper than the SMC, suggesting a lower attenuation at a given beta relative to older/more massive galaxies. The lower attenuations and higher ionizing photon output implied by low metallicity stellar population models point to Lyman continuum production efficiencies, xi_ion, that may be elevated by a factor of \textasciitilde2 relative to the canonical value for L* galaxies, aiding in their ability to keep the universe ionized at z\textasciitilde2. [Abridged]
@article{reddy_hduv_2017,
	title = {The {HDUV} {Survey}: {A} {Revised} {Assessment} of the {Relationship} between {UV} {Slope} and {Dust} {Attenuation} for {High}-{Redshift} {Galaxies}},
	volume = {1705},
	shorttitle = {The {HDUV} {Survey}},
	url = {http://adsabs.harvard.edu/abs/2017arXiv170509302R},
	abstract = {We use a newly assembled large sample of 3,545 star-forming galaxies 
with secure spectroscopic, grism, and photometric redshifts at z=1.5-2.5
to constrain the relationship between UV slope (beta) and dust
attenuation (L(IR)/L(UV)=IRX). Our sample benefits from the combination
of deep Hubble WFC3/UVIS photometry from the Hubble Deep UV (HDUV)
Legacy survey and existing photometric data compiled in the 3D-HST
survey, and extends the range of UV luminosity and beta probed in
previous UV-selected samples. IRX is measured using stacks of deep
Herschel/PACS 100 and 160 micron data, and the results are compared with
predictions of the IRX-beta relation for different assumptions of the
stellar population model and obscuration curve. We find that z=1.5-2.5
galaxies have an IRX-beta relation that is consistent with the
predictions for an SMC extinction curve if we invoke sub-solar
metallicity models that are currently favored for high-redshift
galaxies, while the commonly assumed starburst attenuation curve
over-predicts the IRX at a given beta by a factor of {\textasciitilde}3. The IRX of
high-mass (M*{\textgreater}10{\textasciicircum}9.75 Msun) galaxies is a factor of {\textgreater}4 larger than
that of low-mass galaxies, lending support for the use of stellar mass
as a proxy for attenuation. The commonly observed trend of fainter
galaxies having bluer beta may simply reflect bluer intrinsic UV slopes
for such galaxies, rather than lower obscurations. The IRX-beta for
young/low-mass galaxies implies a dust curve that is steeper than the
SMC, suggesting a lower attenuation at a given beta relative to
older/more massive galaxies. The lower attenuations and higher ionizing
photon output implied by low metallicity stellar population models point
to Lyman continuum production efficiencies, xi\_ion, that may be elevated
by a factor of {\textasciitilde}2 relative to the canonical value for L* galaxies,
aiding in their ability to keep the universe ionized at z{\textasciitilde}2. [Abridged]},
	journal = {ArXiv e-prints},
	author = {Reddy, Naveen A. and Oesch, Pascal A. and Bouwens, Rychard J. and Montes, Mireia and Illingworth, Garth D. and Steidel, Charles C. and van Dokkum, Pieter G. and Atek, Hakim and Carollo, Marcella C. and Cibinel, Anna and Holden, Brad and Labbe, Ivo and Magee, Dan and Morselli, Laura and Nelson, Erica J. and Wilkins, Steve},
	month = may,
	year = {2017},
	keywords = {Astrophysics - Astrophysics of Galaxies},
	pages = {arXiv:1705.09302},
}

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