We present a systematic investigation of the circumgalactic medium (CGM) within projected distances d < 160 kpc of luminous red galaxies (LRGs). The sample comprises 16 intermediatered-shift (z = 0.21-0.55) LRGs of stellar mass M-star > 10(11 )M(circle dot). Combining far-ultraviolet Cosmic Origin Spectrograph spectra from the Hubble Space Telescope and optical echelle spectra from the ground enables a detailed ionization analysis based on resolved component structures of a suite of absorption transitions, including the full H I Lyman series and various ionic metal transitions. By comparing the relative abundances of different ions in individually matched components, we show that cool gas (T similar to 10(4) K) density and metallicity can vary by more than a factor of 10 in an LRG halo. Specifically, metal-poor absorbing components with <1/10 solar metallicity are seen in 50 percent of the LRG haloes, while gas with solar and super-solar metallicity is also common. These results indicate a complex multiphase structure and poor chemical mixing in these quiescent haloes. We calculate the total surface mass density of cool gas, Sigma(cool) by applying the estimated ionization fraction corrections to the observed H column densities. The radial profile of Sigma(cool) is best described by a projected Einasto profile of slope alpha = 1 and scale radius r(s) = 48 kpc. We find that typical LRGs at z similar to 0.4 contain cool gas mass of Sigma(cool) = (1 - 2) x 10(10)M(circle dot) at d < 160 kpc (or as much as Sigma(cool) approximate to 4 x 10(10) M-circle dot at d < 500 kpc), comparable to the cool CGM mass of star-forming galaxies. Furthermore, we show that high-ionization O VI and low-ionization absorption species exhibit distinct velocity profiles, highlighting their different physical origins. We discuss the implications of our findings for the origin and fate of cool gas in LRG haloes.

We report the results from a search for z > 6.5 quasars using the Dark Energy Survey (DES) Year 3 data set combined with the VISTA Hemisphere Survey (VHS) and WISE All-Sky Survey. Our photometric selection method is shown to be highly efficient in identifying clean samples of high-redshift quasars, leading to spectroscopic confirmation of three new quasars -VDES J0244-5008 (z = 6,724), VDES J0020-3653 (z = 6.834), and VDES J0246-5219 (z = 6.90) - which were selected as the highest priority candidates in the survey data without any need for additional follow-up observations. We have obtained spectroscopic observations in the near-infrared for VDES J0244-5008 and VDES J0020-3653 as well as our previously identified quasar, VDES J0224-471 1 at z = 6.50 from Reed et al, We use the near-infrared spectra to derive virial black hole masses from the full width at half-maximum of the Mg II line. These black hole masses are similar or equal to 1-2 x 10(9) M-circle dot. Combined with the bolometric luminosities of these quasars of L-bot similar or equal to 1-3 x 10(47), these imply that the Eddington ratios are high, similar or equal to 0.6-1.1. We consider the C iv emission line properties of the sample and demonstrate that our highredshift quasars do not have unusual C iv line properties when compared to carefully matched low-redshift samples. Our new DES + VHS z > 6.5 quasars now add to the growing census of luminous, rapidly accreting supermassive black holes seen well into the epoch of reionization.

Observing the signature of accretion from the intergalactic medium (IGM) on to galaxies at z similar to 3 requires the detection of faint (L << L*) galaxies embedded in a filamentary matrix of low-density (rho < 100 <(rho)over bar>), metal-poor gas (Z similar to 10(-2.5) Z(circle dot)) coherent over hundreds of kpc. We study the gaseous environment of three Ly alpha emitters (LAEs) at z = 2.7 - 2.8, found to be aligned in projection with a background QSO over similar to 250 kpc along the slit of a long-slit spectrum. The lack of detection of the LAEs in deep continuum images and the low inferred Ly alpha luminosities show the LAEs to be intrinsically faint, low-mass galaxies (L less than or similar to 0.1L*, M-star less than or similar to 0.1M*). An echelle spectrum of the QSO reveals strong Ly alpha absorption within +/- 200 km s(-1) from the LAEs. Our absorption line analysis leads to HI column densities in the range of logN(H I)/cm(-2) = 16-18. Associated absorption from ionic metal species CIV and Si IV constrains the gas metallicities to similar to 0.01 solar if the gas is optically thin, and possibly as low as similar to 0.001 solar if the gas is optically thick, assuming photoionization equilibrium. While the inferred metallicities are at least a factor of 10 lower than expected metallicities in the interstellar medium (ISM) of these LAEs, they are consistent with the observed chemical enrichment level in the IGM at the same epoch. Total metal abundances and kinematic arguments suggest that these faint galaxies have not been able to affect the properties of their surrounding gas. The projected spatial alignment of the LAEs, together with the kinematic quiescence and correspondence between the LAEs and absorbing gas in velocity space, suggests that these observations probe a possible filamentary structure. Taken together with the blue-dominant Ly alpha emission line profile of one of the objects, the evidence suggests that the absorbing gas is part of an accretion stream of low-metallicity gas in the IGM.

We identify a strong Ly? damping wing profile in the spectrum of the quasar P183+05 at z=6.4386. Given the detection of several narrow metal absorption lines at z=6.40392, the most likely explanation for the absorption profile is that it is due to a damped Ly? system. However, in order to match the data a contribution of an intergalactic medium 5%?38% neutral or additional weaker absorbers near the quasar is also required. The absorption system presented here is the most distant damped Ly? system currently known. We estimate an H i column density of 10(20.680.25) cm(?2), metallicity [O/H] = ?2.92 0.32, and relative chemical abundances of a system consistent with a low-mass galaxy during the first Gyr of the universe. This object is among the most metal-poor damped Ly? systems known and, even though it is observed only ?850 Myr after the big bang, its relative abundances do not show signatures of chemical enrichment by Population III stars.

We report the Subaru Hyper Suprime-Cam (HSC) discovery of two Ly alpha blobs (LABs), dubbed z70-1 and z49-1 at z = 6.965 and z = 4.888, respectively, that are Ly alpha emitters with a bright (log Lly alpha/[crg s(-1)] > 43.4 and and spatially extended Ly alpha emission, and present the photometric and spectroscopic properties of a total of seven LABs: the two new LABs and five previously known LABs at z = 5.7-6.6. The z70-1 LAB shows extended Ly alpha emission with a scale length of 1.4 +/- 0.2 kpc, about three times larger than the UV continuum emission, making z70-1 the most distant LAB identified to date. All of the seven LABs, except z49-1, exhibit no active galactic nucleus (AGN) signatures such as X-ray emission, N v lambda 1240 emission, or Ly alpha line broadening, while z49-1 has a strong C iv lambda 1548 emission line indicating an AGN on the basis of the UV-line ratio diagnostics. We carefully model the point-spread functions of the HSC images and conduct two-component exponential profile fitting to the extended Ly alpha emission of the LABs. The Ly alpha scale lengths of the core (star-forming region) and halo components are r(c) = 0.6-1.2 kpc and r(h) = 2.0-13.8 kpc, respectively. The relations between the scale lengths and galaxy properties (Ly alpha luminosity L-Ly alpha, Ly alpha rest-frame equivalent width EW0, and UV continuum magnitude M-UV) of our LABs are similar to those of Ly alpha halos (LAHs) identified around star-forming galaxies found previously by the Very Large Telescope/MUSE at similar redshifts, suggesting that our LABs are likely the bright version of high-z LAHs.

We report the first detection of multiphase gas within a quiescent galaxy beyond z approximate to 0. The observations use the brighter image of doubly lensed QSO HE 0047-1756 to probe the interstellar medium (ISM) of the massive (M-star approximate to 10(11) M-circle dot) elliptical lens galaxy at z(gal) = 0.408. Using Hubble Space Telescope's Cosmic Origins Spectrograph (COS), we obtain a medium-resolution FUV spectrum of the lensed QSO and identify numerous absorption features from H-2 in the lens ISM at projected distance d = 4.6 kpc. The H-2 column density is log N(H-2)/cm(-2) 17.8(-0.3)(+0.1) with a molecular gas fraction of f(H2) = 2%-5% , roughly consistent with some local quiescent galaxies. The new COS spectrum also reveals kinematically complex absorption features from highly ionized species O VI and N V with column densities log N(O VI) cm(-2) = 15.2 +/- 0.1 and log N(N V) cm(-2) = 14.6 +/- 0.1, among the highest known in external galaxies. Assuming the high-ionization absorption features originate in a transient warm (T similar to 105 K) phase undergoing radiative cooling from a hot halo surrounding the galaxy, we infer a mass accretion rate of similar to 0.5-1.5 M-circle dot yr(-1). The lack of star formation in the lens suggests that the bulk of this flow is returned to the hot halo, implying a heating rate of similar to 1048 erg yr(-1). Continuous heating from evolved stellar populations (primarily SNe Ia but also winds from AGB stars) may suffice to prevent a large accumulation of cold gas in the ISM, even in the absence of strong feedback from an active nucleus.

The nearby Type Ia supernova (SN Ia) SN 2011fe in M101 (cz = 241 km s(-1)) provides a unique opportunity to study the early evolution of a "normal" SN Ia, its compositional structure, and its elusive progenitor system. We present 18 high signal-to-noise spectra of SN 2011fe during its first month beginning 1.2 days post-explosion and with an average cadence of 1.8 days. This gives a clear picture of how various line-forming species are distributed within the outer layers of the ejecta, including that of unburned material (C+O). We follow the evolution of C II absorption features until they diminish near maximum light, showing overlapping regions of burned and unburned material between ejection velocities of 10,000 and 16,000 km s(-1). This supports the notion that incomplete burning, in addition to progenitor scenarios, is a relevant source of spectroscopic diversity among SNe Ia. The observed evolution of the highlyDoppler-shifted OI lambda 7774 absorption features detected within 5 days post-explosion indicates the presence of OI with expansion velocities from 11,500 to 21,000 km s(-1). The fact that some OI is present above C II suggests that SN 2011fe may have had an appreciable amount of unburned oxygen within the outer layers of the ejecta.

Current time domain facilities are finding several hundreds of transient astronomical events a year. The discovery rate is expected to increase in the future as soon as new surveys such as the Zwicky Transient Facility (ZTF) and the Large Synoptic Sky Survey (LSST) come online. Presently, the rate at which transients are classified is approximately one order or magnitude lower than the discovery rate, leading to an increasing "follow-up drought". Existing telescopes with moderate aperture can help address this deficit when equipped with spectrographs optimized for spectral classification. Here, we provide an overview of the design, operations and first results of the Spectral Energy Distribution Machine (SEDM), operating on the Palomar 60-inch telescope (P60). The instrument is optimized for classification and high observing efficiency. It combines a low-resolution (R similar to 100) integral field unit (IFU) spectrograph with "Rainbow Camera" (RC), a multi-band field acquisition camera which also serves as multi-band (ugri) photometer. The SEDM was commissioned during the operation of the intermediate Palomar Transient Factory (iPTF) and has already lived up to its promise. The success of the SEDM demonstrates the value of spectrographs optimized for spectral classification.

High-cadence transient surveys are able to capture supernovae closer to their first light than ever before. Applying analytical models to such early emission, we can constrain the progenitor stars' properties. In this paper, we present observations of SN 2018fif (ZTF 18abokyfk). The supernova was discovered close to first light and monitored by the Zwicky Transient Facility (ZTF) and the Neil Gehrels Swift Observatory. Early spectroscopic observations suggest that the progenitor of SN 2018fif was surrounded by relatively small amounts of circumstellar material compared to all previous cases. This particularity, coupled with the high-cadence multiple-band coverage, makes it a good candidate to investigate using shock-cooling models. We employ the SOPRANOS code, an implementation of the model by Sapir & Waxman and its extension to early times by Morag et al. Compared with previous implementations, SOPRANOS has the advantage of including a careful account of the limited temporal validity domain of the shock-cooling model as well as allowing usage of the entirety of the early UV data. We find that the progenitor of SN 2018fif was a large red supergiant with a radius of R = 744.0(-128.0)(+183.0) R-circle dot and an ejected mass of M-ej = 9.3(-5.8)(+0.4) M-circle dot. Our model also gives information on the explosion epoch, the progenitor's inner structure, the shock velocity, and the extinction. The distribution of radii is double-peaked, with smaller radii corresponding to lower values of the extinction, earlier recombination times, and a better match to the early UV data. If these correlations persist in future objects, denser spectroscopic monitoring constraining the time of recombination, as well as accurate UV observations (e.g., with ULTRASAT), will help break the extinction/radius degeneracy and independently determine both.

We present a spectrophotometric survey of 2522 extragalactic globular clusters (GCs) around 12 early-type galaxies, nine of which have not been published previously. Combining space-based and multicolour wide-field ground-based imaging, with spectra from the Keck/DEep Imaging Multi-Object Spectrograph (DEIMOS) instrument, we obtain an average of 160 GC radial velocities per galaxy, with a high-velocity precision of similar to 15 km s(-1) per GC. After studying the photometric properties of the GC systems, such as their spatial and colour distributions, we focus on the kinematics of metal-poor (blue) and metal-rich (red) GC subpopulations to an average distance of similar to 8 effective radii from the galaxy centre.