Citation for published item:rohskD tF vier nd erkD tessi uF nd orsekD q¡ or nd rippD odd wF nd umlinsonD tson nd furhettD toseph xF nd poxD endrew tF nd pumglliD wihele nd vehnerD xiols nd eeplesD wolly F nd ejosD xiols @PHIUA 9he gyErlos survey X metlliities in the lowEredshift irumglti mediumF9D estrophysil journlFD VQU @PAF pF ITWF Further information on publisher's website: Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractWe analyze new far-ultraviolet spectra of 13quasars from thez 0.2 COS-Halos survey that cover the H I Lyman limit of 14circumgalactic medium (CGM) systems. These data yield precise estimates or more constraining limits than previous COS-Halos measurements on the H I column densities N H I . We then apply a Monte-Carlo Markov chain approach on 32systems from COS-Halos to estimate the metallicity of the cool (T 10 4 K) CGM gas that gives rise to low-ionization state metal lines, under the assumption of photoionization equilibrium with the extragalactic UV background. The principle results are: (1) the CGM of field L * galaxies exhibits a declining H I surface density with impact parameterR (at >99.5% confidence), (2) the transmission of ionizing radiation through CGM gas alone is 70±7%; (3) the metallicity distribution function of the cool CGM is unimodal with a median of - to >  Z 3 ; the incidence of metal-poor (<  Z 1 100 ) gas is low, implying any such gas discovered along quasar sightlines is typically unrelated to L * galaxies; (4) we find an unexpected increase in gas metallicity with declining N H I (at >99.9% confidence) and, therefore, also with increasingR ; the high metallicity at large radii implies early enrichment; and (5) a non-parametric estimate of the cool CGM gas mass is = ´ ( ) M M 9.2 4.3 10 CGM cool 10, which together with new mass estimates for the hot CGM may resolve the galactic missing baryons problem. Future analyses of halo gas should focus on the underlying astrophysics governing the CGM, rather than processes that simply expel the medium from the halo.

We report new observations of circumgalactic gas from the COS-Dwarfs survey, a systematic investigation of the gaseous halos around 43 low-mass z ≤ 0.1 galaxies using background QSOs observed with the Cosmic Origins Spectrograph. From the projected 1D and 2D distribution of C IV absorption, we find that C IV is detected out to ≈ 100 kpc (corresponding roughly to ≈ 0.5 R vir ) of the host galaxies. The C IV absorption strength falls off radially as a power law and beyond ≈ 0.5 R vir , no C IV absorption is detected above our sensitivity limit of ≈ 50-100 mÅ. We find a tentative correlation between detected C IV absorption strength and star formation, paralleling the strong correlation seen in highly ionized oxygen for L∼L * galaxies by the COS-Halos survey. The data imply a large carbon reservoir in the CGM of these galaxies, corresponding to a minimum carbon mass of 1.2 × 10 6 M ⊙ out to ∼ 110 kpc. This mass is comparable to the carbon mass in the ISM and exceeds the carbon mass currently in the stars of these galaxies. The C IV absorption seen around these sub-L * galaxies can account for almost two-thirds of all W r ≥ 100 mÅ C IV absorption detected at low z. Comparing the C IV covering fraction with hydrodynamical simulations, we find that an energy-driven wind model is consistent with the observations whereas a wind model of constant velocity fails to reproduce the CGM or the galaxy properties.

Fast Radio Bursts (FRBs) are brief radio emissions from distant astronomical sources. Some are known to repeat, but most are single bursts. Non-repeating FRB observations have had insufficient positional accuracy to localize them to an individual host galaxy. We report the interferometric localization of the single pulse FRB 180924 to a position 4 kpc from the center of a luminous galaxy at redshift 0.3214. The burst has not been observed to repeat. The properties of the burst and its host are markedly different from the only other accurately localized FRB source. The integrated electron column density along the line of sight closely matches models of the intergalactic medium, indicating that some FRBs are clean probes of the baryonic component of the cosmic web.Cosmological observations have shown that baryons comprise 4% of the energy density of the Universe, of which only about 10% is in cold gas and stars (1), with the remainder residing in a diffuse plasma surrounding and in between galaxies and galaxy clusters. The location and density of this material has been challenging to characterize, and up to 50% of it remains unaccounted (2).Fast radio bursts (FRBs; ref.(3)) are bright bursts of radio waves with millisecond duration. They can potentially be used to detect, study, and map this medium, as bursts of emission are dispersed and scattered by their 1 arXiv:1906.11476v1 [astro-ph.HE] 27 Jun 2019 dual-polarization beams on the sky using digital beamforming, producing a total field-of-view of ∼ 30 deg 2 . For burst detection, the beamformers produces channelized autocorrelation spectra for both linear polarizations of all beams, with an integration time of 864 µs and channel bandwidth of 1 MHz in these observations. We used 336 channels centered at 1320 MHz. A real-time detection pipeline incoherently adds the spectra from all available antennas (24 antennas in these observations) and polarization channels, then searches (16) the result for dispersed pulses (17).Burst localization is completed with a second data product that utilizes both the amplitude and phase information of the burst radiation. The beamformers store samples of the complex electric field for all beams and both polarizations in a ring buffer of 3.1 s duration, with the oldest data being continuously overwritten by new data. The data are saved for offline interferometric analysis only when the pipeline identifies a candidate. For the searches reported here the triggering required pulses with widths less than 9 ms and S/N > 10.Previous searches with ASKAP used antennas pointed in different directions to maximize sky coverage (10,16). In contrast, our observations used antennas all pointed in the same direction, enabling the array to act as an interferometer capable of sub-arcsecond localization with a 30 deg 2 field of view. We targeted high Galactic latitude fields (Galactic latitude |b| ∼ 50 • ), that had been observed previously (10, 16), and Southern circumpolar fields. The high-latitude fields were observed regularly through 2017 and earl...

This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 survey that publicly releases infrared spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the subsurvey Time Domain Spectroscopic Survey data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey subsurvey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated value-added catalogs. This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper, Local Volume Mapper, and Black Hole Mapper surveys.

Using Hubble Space Telescope Cosmic Origins Spectrograph observations of 89 QSO sightlines through the Sloan Digital Sky Survey footprint, we study the relationships between C iv absorption systems and the properties of nearby galaxies as well as large-scale environment. To maintain sensitivity to very faint galaxies, we restrict our sample to 0.0015 < z < 0.015, which defines a complete galaxy survey to L 0.01 L * or stellar mass M * 10 8 M . We report two principal findings. First, for galaxies with impact parameter ρ < 1 r vir , C iv detection strongly depends on the luminosity/stellar mass of the nearby galaxy. C iv is preferentially associated with galaxies with M * > 10 9.5 M ; lower mass galaxies rarely exhibit significant C iv absorption (covering fraction f C = 9 +12 −6 % for 11 galaxies with M * < 10 9.5 M ). Second, C iv detection within the M * > 10 9.5 M population depends on environment. Using a fixed-aperture environmental density metric for galaxies with ρ < 160 kpc at z < 0.055, we find that 57 +12 −13 % (8/14) of galaxies in low-density regions (regions with fewer than seven L > 0.15 L * galaxies within 1.5 Mpc) have affiliated C iv absorption; however, none (0/7) of the galaxies in denser regions show C iv. Similarly, the C iv detection rate is lower for galaxies residing in groups with dark-matter halo masses of M halo > 10 12.5 M . In contrast to C iv, H i is pervasive in the CGM without regard to mass or environment. These results indicate that C iv absorbers with log N (C iv) 13.5 cm −2 trace the halos of M * > 10 9.5 M galaxies but also reflect larger scale environmental conditions.