Speaker
Description
The circumgalactic/intergalactic medium (CGM/IGM) represents a significant baryon reservoir for sustaining star formation and provides insights into the inflows, outflows, and feedback history of galaxies. Star-forming dwarf galaxies, with their shallow potential wells, are predicted to drive metal-enriched gas into the CGM/IGM. Therefore, a census of the CGM around dwarf galaxies can provide insights into the stellar feedback. We present highly sensitive absorption-line measurements in quasar sightlines adjacent to 91 isolated dwarf galaxies with a median stellar mass of M_star/M_sun≈8.4 from the Cosmic Ultraviolet Baryon Survey (CUBS). This survey uses HST absorption spectroscopy to access a range of ion transitions from 0.077<z<0.73 such as the Lyman-series transitions for HI, as well as a range of multiphase metal lines including low (e.g. CII, SiII), intermediate (e.g. CIII, SiIII) and high (e.g. CIV, OVI) ions. The CUBS Dwarfs sample represents a nine-fold increase in the number of star-forming field dwarf galaxies with CGM constraints on neutral hydrogen and metal absorption lines. We find that low and intermediate ionization metal absorption is rare and limited to the inner CGM of dwarf galaxies. In contrast, highly ionized OVI is commonly observed in sightlines that pass within the virial radius of a dwarf, and OVI detection rates are non-negligible at projected distances of 1-2x the virial radius. These measurements show that the OVI-bearing phase of the CGM/IGM accounts for the majority of the oxygen budget from star-formation, and the kinematic distribution of absorption systems suggests that a relatively modest fraction of this gas is formally unbound from the halo. Time permitting, I will show photoionization analysis of one system with evidence of absorption in the inner-CGM with ɑ-enhancement characteristic of core-collapse supernovae driven winds.
| Primary Theme | Galactic to intergalactic scales |
|---|---|
| Secondary Theme | Hot gas to cold gas |
| Presenter's Name | Nishant Mishra |
| Presenter's Email Address | [email protected] |
| Keywords | Circumgalactic Medium, Dwarf Galaxies, Absorption Line Spectroscopy, Feedback, Supernova-driven Winds |
| Recording Permission | YES |
| Virtual Audience Permission | YES |
| Photography Permission | YES |
| If your talk is not accepted for a contributed talk, would you be interested in presenting a fireslide/lightning talk? | Yes |
| If your fireslide/lighting talk is not accepted, would you be interested in presenting a poster? | Yes |
Author
External references
- 25070058
- d47ffd0b-99f1-4322-b4e8-74fb747824b7
