The USNO eXtremely Metal-Poor Galaxy Survey (UXMPS)
Abstract
Extremely metal-poor galaxies (XMPs) are the closest local analogs to primordial galaxies first formed at the earliest epochs of the universe, when the lack of metallicity enrichment from stellar byproducts affected the stellar initial mass function, the prevalence and luminosities of X-ray binaries, the ionization state of the interstellar medium, and the formation mechanism of the first massive black holes. Despite the importance of XMPs to our understanding of the earliest epochs, very little is known about these galaxies, and even less is understood about their near-IR properties, where XMPs are generally very faint owing to their lack of old stellar populations. This is a major deficiency, as the near-IR is where important phenomena, such as high-ionization coronal lines produced by accretion onto black holes, is found. We present a dedicated survey led by USNO, using WFCAM on UKIRT, to produce a near-IR YJHK photometric catalog of confirmed XMPs. This catalog is complemented by matched grizy photometry from Pan-STARRS, using forced photometry to maximize sensitivity and produce useful photometry in every band. With exquisite photometry in 9 bands covering 0.5 to 2.4 micron, precise modeling of the spectral energy distributions of XMPs using recent theoretic models is possible, yielding key insights into the properties of the first galaxies in the universe. Finally, because of the large field of view of WFCAM, we serendipitously detect tens of thousands of other objects, which we provide grizyYJHK photometry for as a service to the broader astronomical community. This survey underscores the critical importance of UKIRT over the coming decade as astrophysics becomes more dominated by studies in the near-IR.
- Publication:
-
American Astronomical Society Meeting Abstracts #235
- Pub Date:
- January 2020
- Bibcode:
- 2020AAS...23520737S