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The object Mayall II or G1 is the brightest globular cluster belonging to M31. Because of its extreme properties for a globular cluster, it has been speculated that G1 is the remnant nucleus of a dwarf galaxy that has been stripped by the tidal field of M31. Using the Keck DEIMOS spectrograph, we have conducted a survey for tidally stripped stars from G1, obtaining a sample of 351 stellar velocities over ∼320 sq. arcmin of sky centred on G1. 13 are within $25~{\, \rm km\, s^{-1}\, }$ of the systemic velocity of G1, and exhibit spatial and velocity correlations consistent with being dynamically associated with G1, and all 13 are well outside the tidal radius of the cluster. These 13 stars could be either (i) the remnants of an almost completely evaporated stellar envelope or (ii) G1 member stars lost through tidal interaction with M31. Estimates of the implied mass-loss rate based on our data suggest a short dissolution time-scale for G1, thus favouring the stellar envelope hypothesis for the origin of the tidal tail stars, or, at the very least, an advanced stage of cluster dissolution. In either case, G1 and by extension compact stellar systems in general have likely played a significant role in building the halo of M31.

Context. Globular clusters (GCs) are witnesses of the past accretion events onto the Milky Way (MW). In particular, the GCs of the Sagittarius (Sgr) dwarf galaxy are important probes of an on-going merger. Aims. Our main goal is to search for new GC members of this dwarf galaxy using the VISTA Variables in the Via Lactea Extended Survey (VVVX) near-infrared database combined with the Gaia Early Data Release 3 (EDR3) optical database. Methods. We investigated all VVVX-enabled discoveries of GC candidates in a region covering about 180 sq. deg. toward the bulge and the Sgr dwarf galaxy. We used multiband point-spread function photometry to obtain deep color-magnitude diagrams (CMDs) and luminosity functions (LFs) for all GC candidates, complemented by accurate Gaia-EDR3 proper motions (PMs) to select Sgr members and variability information to select RR Lyrae which are potential GC members. Results. After applying a strict PM cut to discard foreground bulge and disk stars, the CMDs and LFs for some of the GC candidates exhibit well defined red giant branches and red clump giant star peaks. We selected the best Sgr GCs, estimating their distances, reddenings, and associated RR Lyrae. Conclusions. We discover 12 new Sgr GC members, more than doubling the number of GCs known in this dwarf galaxy. In addition, there are 11 other GC candidates identified that are uncertain, awaiting better data for confirmation., Comment: 12 pages, 6 Figures

The discovery of Proxima b, a terrestrial temperate planet, presents the opportunity of studying a potentially habitable world in optimal conditions. A key aspect to model its habitability is to understand the radiation environment of the planet in the full spectral domain. We characterize the X-rays to mid-IR radiative properties of Proxima with the goal of providing the top-of-atmosphere fluxes on the planet. We also aim at constraining the fundamental properties of the star. We employ observations from a large number of facilities and make use of different methodologies to piece together the full spectral energy distribution of Proxima. In the high-energy domain, we pay particular attention to the contribution by rotational modulation, activity cycle, and flares so that the data provided are representative of the overall radiation dose received by the atmosphere of the planet. We present the full spectrum of Proxima covering 0.7 to 30000 nm. The integration of the data shows that the top-of-atmosphere average XUV irradiance on Proxima b is 0.293 W m^-2, i.e., nearly 60 times higher than Earth, and that the total irradiance is 877+/-44 W m^-2, or 64+/-3% of the solar constant but with a significantly redder spectrum. We also provide laws for the XUV evolution of Proxima corresponding to two scenarios. Regarding the fundamental properties of Proxima, we find M=0.120+/-0.003 Msun, R=0.146+/-0.007 Rsun, Teff=2980+/-80 K, and L=0.00151+/-0.00008 Lsun. In addition, our analysis reveals a ~20% excess in the 3-30 micron flux of the star that is best interpreted as arising from warm dust in the system. The data provided here should be useful to further investigate the current atmospheric properties of Proxima b as well as its past history, with the overall aim of firmly establishing the habitability of the planet., Comment: 12 pages, 5 figures, accepted for publication in Astronomy & Astrophysics

We use our integrated SDSS photometry for 96 globular clusters in $g$ and $z$, as well as $r$ and $i$ photometry for a subset of 56 clusters, to derive the integrated colour-metallicity relation (CMR) for Galactic globular clusters. We compare this relation to previous work, including extragalactic clusters, and examine the influence of age, present-day mass function variations, structural parameters and the morphology of the horizontal branch on the relation. Moreover, we scrutinise the scatter introduced by foreground extinction (including differential reddening) and show that the scatter in the colour-metallicity relation can be significantly reduced combining two reddening laws from the literature. In all CMRs we find some low-reddening young GCs that are offset to the CMR. Most of these outliers are associated with the Sagittarius system. Simulations show that this is due less to age than to a different enrichment history. Finally, we introduce colour-metallicity relations based on the infrared Calcium triplet, which are clearly non-linear when compared to $(g^\prime-i^\prime)$ and $(g^\prime-z^\prime)$ colours., Accepted for publication in MNRAS. 17 pages, 18 figures

Compact stellar systems (CSS) range in mass from globular clusters (GCs), through the more recently discovered ultracompact dwarfs (UCDs), to the rare compact elliptical galaxies. Given their intermediate position, the origin of UCDs, and hence whether they should be counted as galaxies or star clusters, remains unclear. In this paper, we compare the population of X-ray point sources (expected to be low-mass X-ray binaries; LMXBs) in UCD candidates, that is, relatively high-luminosity compact systems, with that known to exist in lower mass GCs. Any difference in LMXB populations may then indicate physical differences between GCs and UCDs. We find that, despite their much larger masses and hence numbers of stars, UCDs and UCD candidates are, if anything, less likely to contain bright X-ray point sources than are GCs. The LMXB content per unit stellar mass is therefore much lower for the UCD candidates, intermediate between that for GCs and for elliptical galaxies. This difference between UCDs and GCs can be explained if UCDs have significantly lower central densities than lower mass GCs, as this will reduce the stellar encounter rate and therefore the production of suitable binary systems. This supports the previously proposed idea of structural differences between UCDs and GCs, though not necessarily ruling out a close relationship between these two types of CSS.

We have observed a dramatic change in the spectrum of the formerly heavily absorbed `overlapping-trough' iron low-ionization broad absorption line (FeLoBAL) quasar FBQS J1408+3054. Over a time span of between 0.6 to 5 rest-frame years, the Mg II trough outflowing at 12,000 km/s decreased in equivalent width by a factor of two and the Fe II troughs at the same velocity disappeared. The most likely explanation for the variability is that a structure in the BAL outflow moved out of our line of sight to the ultraviolet continuum emitting region of the quasar's accretion disk. Given the size of that region, this structure must have a transverse velocity of between 2600 km/s and 22,000 km/s. In the context of a simple outflow model, we show that this BAL structure is located between approximately 5800 and 46,000 Schwarzschild radii from the black hole. That distance corresponds to 1.7 to 14 pc, 11 to 88 times farther from the black hole than the H-beta broad-line region. The high velocities and the parsec-scale distance for at least this one FeLoBAL outflow mean that not all FeLoBAL outflows can be associated with galaxy-scale outflows in ultraluminous infrared galaxies transitioning to unobscured quasars. The change of FBQS J1408+3054 from an FeLoBAL to a LoBAL quasar also means that if (some) FeLoBAL quasars have multiwavelength properties which distinguish them from HiBAL quasars, then some LoBAL quasars will share those properties. Finally, we extend previous work on how multiple-epoch spectroscopy of BAL and non-BAL quasars can be used to constrain the average lifetime of BAL episodes (currently >60 rest-frame years at 90% confidence).

We present results on a survey to find extremely dust-reddened Type-1 Quasars. Combining the FIRST radio survey, the 2MASS Infrared Survey and the Sloan Digital Sky Survey, we have selected a candidate list of 122 potential red quasars. With more than 80% spectroscopically identified objects, well over 50% are classified as dust-reddened Type 1 quasars, whose reddenings (E(B-V)) range from approximately 0.1 to 1.5 magnitudes. They lie well off the color selection windows usually used to detect quasars and many fall within the stellar locus, which would have made it impossible to find these objects with traditional color selection techniques. The reddenings found are much more consistent with obscuration happening in the host galaxy rather than stemming from the dust torus. We find an unusually high fraction of Broad Absorption Line (BAL) quasars at high redshift, all but one of them belonging to the Low Ionization BAL (LoBAL) class and many also showing absorption the metastable FeII line (FeLoBAL). The discovery of further examples of dust-reddened LoBAL quasars provides more support for the hypothesis that BAL quasars (at least LoBAL quasars) represent an early stage in the lifetime of the quasar. The fact that we see such a high fraction of BALs could indicate that the quasar is in a young phase in which quasar feedback from the BAL winds is suppressing star formation in the host galaxy., 17 pages, 7 figures, accepted for publication in ApJ

All the previously cataloged ultracompact dwarf (UCD) galaxies in the Fornax and Virgo clusters have 17.5

We present a detailed analysis of two-band HST/ACS imaging of 21 ultra-compact dwarf (UCD) galaxies in the Virgo and Fornax Clusters. The aim of this work is to test two formation hypotheses for UCDs--whether they are bright globular clusters (GCs) or "threshed'' early-type dwarf galaxies--by comparison of UCD structural parameters and colors with GCs and galaxy nuclei. We find that the UCD surface brightness profiles can be described by a range of models and that the luminous UCDs can not be described by standard King models with tidal cutoffs as they have extended outer halos. This is not expected from traditional King models of GCs, but is consistent with recent results for massive GCs. The total luminosities, colors and sizes of the UCDs are consistent with them being either luminous GCs or threshed nuclei of both early-type and late-type galaxies (not just early-type dwarfs). For the most luminous UCDs we estimate color gradients over a limited range of radius. These are systematically positive in the sense of getting redder outwards: mean Delta(F606W-F814W)=0.14 mag per 100 pc with rms=0.06 mag per 100 pc. The positive gradients found in the bright UCDs are consistent with them being either bright GCs or threshed early-type dwarf galaxies (except VUCD3). In contrast to the above results we find a very significant difference in the sizes of UCDs and early-type galaxy nuclei: the effective radii of UCDs are 2.2 times larger than those of early-type galaxy nuclei at the same luminosity. This result suggests an important test can be made of the threshing hypothesis by simulating the process and predicting what size increase is expected., 29 pages, 16 figures, accepted for publication in The Astronomical Journal

We report the first results of our systematic search for strongly lensed quasars using the spectroscopically confirmed quasars in the Sloan Digital Sky Survey (SDSS). Among 46,420 quasars from the SDSS Data Release 3 (~4188 deg^2), we select a subsample of 22,683 quasars that are located at redshifts between 0.6 and 2.2 and are brighter than the Galactic extinction corrected i-band magnitude of 19.1. We identify 220 lens candidates from the quasar subsample, for which we conduct extensive and systematic follow-up observations in optical and near-infrared wavebands, in order to construct a complete lensed quasar sample at image separations between 1'' and 20'' and flux ratios of faint to bright lensed images larger than 10^{-0.5}. We construct a statistical sample of 11 lensed quasars. Ten of these are galaxy-scale lenses with small image separations (~1''-2'') and one is a large separation (15'') system which is produced by a massive cluster of galaxies, representing the first statistical sample of lensed quasars including both galaxy- and cluster-scale lenses. The Data Release 3 spectroscopic quasars contain an additional 11 lensed quasars outside the statistical sample., Comment: 15 pages, 4 figures, 5 tables, accepted for publication in AJ; see http://www-utap.phys.s.u-tokyo.ac.jp/~sdss/sqls/ for supplemental information

We have obtained spectroscopic redshifts of colour-selected point sources in four wide area VLT-FLAMES fields around the Fornax Cluster giant elliptical galaxy NGC 1399, identifying as cluster members 30 previously unknown faint (-10.5, Comment: 13 pages (including supplementary table), 13 figures, 5 tables. Accepted for publication in MNRAS

We present the results of a search for ultra-compact dwarf galaxies (UCDs) in six different galaxy groups: Dorado, NGC1400, NGC0681, NGC4038, NGC4697 and NGC5084. We searched in the apparent magnitude range 17.5 < b_j < 20.5 (except NGC5084: 19.2 < b_j < 21.0). We found 1 definite plus 2 possible UCD candidates in the Dorado group and 2 possible UCD candidates in the NGC1400 group. No UCDs were found in the other groups. We compared these results with predicted luminosities of UCDs in the groups according to the hypothesis that UCDs are globular clusters formed in galaxies. The theoretical predictions broadly agree with the observational results, but deeper surveys are needed to fully test the predictions., 8 pages, 2 figures, accepted for publication in MNRAS

Aims. We determine masses and mass-to-light ratios of five ultra-compact dwarf galaxies and one dwarf elliptical nucleus in the Fornax cluster from high resolution spectroscopy. Methods. Velocity dispersions were derived from selected wavelength regions using a direct-fitting method. To estimate the masses of the UCDs a new modelling program has been developed that allows a choice of different representations of the surface brightness profile (i.e. Nuker, Sersic or King laws) and corrects the observed velocity dispersions for observational parameters (i.e. seeing, slit size). Results. The observed velocity dispersions range between 22 and 30 km/s. The resulting masses are between 1.8 and 9.5x10^7M_sun. These, as well as the central and global projected velocity dispersions, were derived from the generalized King model which turned out to give the most stable results. The masses of two UCDs, that are best fitted by a two-component profile, were derived from a combined King+Sersic model. The mass-to-light ratios of the Fornax UCDs range between 3 and 5 (M/L_V)_sun. Within 1-2 half-mass radii dark matter is not dominating UCDs. Conclusions. We show that the mass-to-light ratios of UCDs in Fornax are consistent with those expected for pure stellar populations. Thus UCDs seem to be the result of cluster formation processes within galaxies rather than being compact dark matter dominated substructures themselves. Whether UCDs gained their mass in super-star cluster complexes of mergers or in nuclear star cluster formation processes remains an open question. It appears, however, clear that star clusters more massive than about 5\times10^6M_sun exhibit a more complex formation history than the less massive `ordinary' globular clusters., Comment: 14 pages, 11 figures, accepted for publication in Astronomy & Astrophysics

We report on a search for faint (R total magnitude fainter than 21) and low surface brightness galaxies (R central surface brightness fainter than ~24) (fLSBs) in a 0.72x0.82 deg2 area centered on the Coma cluster. We analyzed deep B and R band CCD imaging obtained using the CFH12K camera at CFHT and found 735 fLSBs. The total B magnitudes, at the Coma cluster redshift, range from -13 to -9 with B central surface brightness as faint as 27 mag/arcsec2. Using empty field comparisons, we show that most of these fLSBs are probably inside the Coma cluster. We present the results of comparing the projected fLSB distributions with the distributions of normal galaxies and with known X-ray over densities. We also investigate their projected distribution relative to their location in the color magnitude relation. Colors of fLSBs vary between B-R~0.8 and ~1.4 for 2/3 of the sample and this part is consistent with the known CMR red-sequence for bright (R, To be published in A&A, 3 jpeg figures, data and full resolution article can be retrieved from http://cencosw.oamp.fr/. Updated CFHT ackowledgements

We have detected FIRST J101614.3+520916 with the XMM-Newton X-ray Observatory. FIRST J101614.3+520916, one of the most extreme radio-loud, broad absorption line (BAL) quasars so far discovered, is also a Fanaroff-Riley type II (FR II) radio source. We find that, compared to its estimated intrinsic X-ray flux, the observed X-rays are likely suppressed, and that the observed hardness ratio indicates significant soft X-ray photons. This is inconsistent with the simplest model, a normal quasar spectrum absorbed by a large neutral HI column density, which would primarily absorb the softer photons. More complex models, involving partial covering, an ionized absorber, ionized mirror reflection, or jet contributions need to be invoked to explain this source. The suppressed but soft X-ray emission in this radio-loud BAL quasar is consistent with the behavior displayed by other BAL quasars, both radio-loud and radio-quiet.

By combining the Sloan Digitized Sky Survey Third Data Release quasar list with the VLA FIRST survey, we have identified five objects having both broad absorption lines in their optical spectra and FR-II radio morphologies. We identify an additional example of this class from the FIRST Bright Quasar Survey, J1408+3054. Including the original FR-II-BAL object, J1016+5209, brings the number of such objects to eight. These quasars are relatively rare; finding this small handful has required the 45,000-large quasar sample of SDSS. The FR-II-BAL quasars exhibit a significant anti-correlation between radio-loudness and the strength of the BAL features. This is easily accounted for by the evolutionary picture in which quasars emerge from cocoons of BAL-producing material which stifle the development of radio jets and lobes. There is no such simple explanation for the observed properties of FR-II-BALs in the unification-by-orientation model of quasars. The rarity of the FR-II-BAL class implies that the two phases do not coexist for very long in a single quasar, perhaps less than 10{sup 5} years, with the combined FR-II, high ionization broad absorption phase being even shorter by another factor of 10 or more.

We report the discovery of a new two-image gravitationally lensed quasar, SDSS J024634.11-082536.2 (SDSS J0246-0825). This object was selected as a lensed quasar candidate from the Sloan Digital Sky Survey (SDSS) by the same algorithm that was used to discover other SDSS lensed quasars (e.g., SDSS J0924+0219). Multicolor imaging with the Magellan Consortium's Walter Baade 6.5-m telescope and the spectroscopic observations using the W. M. Keck Observatory's Keck II telescope confirm that SDSS J0246-0825 consists of two lensed images ($\Delta{\theta}=$1\farcs04) of a source quasar at z=1.68. Imaging observations with the Keck telescope and the Hubble Space Telescope reveal an extended object between the two quasar components, which is likely to be a lensing galaxy of this system. From the absorption lines in the spectra of quasar components and the apparent magnitude of the galaxy, combined with the expected absolute magnitude from the Faber-Jackson relation, we estimate the redshift of the lensing galaxy to be z=0.724. A highly distorted ring is visible in the Hubble Space Telescope images, which is likely to be the lensed host galaxy of the source quasar. Simple mass modeling predicts the possibility that there is a small (faint) lensing object near the primary lensing galaxy.

We report the results of a Chandra X-Ray Observatory survey of five formally radio-loud broad absorption line (BAL) quasars. These five objects include BAL quasars with a range of properties, including both high- and low-ionization BALs. All five BAL quasars are detected in 5 ks ACIS-S exposures, with counts ranging from 12 to 55. The X-ray count rates are down by factors of 40 or more compared to expectations based on the spectral energy distributions of normal, unabsorbed radio-loud quasars; this is the same sort of behavior seen in radio-quiet BAL quasars. Interestingly, the hardness ratios are rather soft and inconsistent with absorption from a neutral hydrogen column density large enough to suppress the X-rays as observed. We conclude that in many cases the X-rays emanating from BAL quasars must be reflected, scattered, or leaked through an ionized absorber or a neutral absorber that does not completely cover the X-ray source (covering ≥98%), or that we are seeing an unabsorbed X-ray source perhaps associated with a radio jet. Much higher counts are required to distinguish among these possibilities. We note several suggestive correlations involving X-ray properties that require verification using larger samples. One source, FIRST J1556+3517, appears to be the X-ray brightest low-ionization BAL quasar known, other than the special case of the nearby Mrk 231. The very faint X-ray emission from FIRST J1044+3656 is consistent with significant obscuration, which strongly favors the multiphase X-ray shielding models of this object in the literature.

We report the discovery of two doubly-imaged quasars, SDSS J100128.61+502756.9 and SDSS J120629.65+433217.6, at redshifts of 1.838 and 1.789 and with image separations of 2.86'' and 2.90'', respectively. The objects were selected as lens candidates from the Sloan Digital Sky Survey (SDSS). Based on the identical nature of the spectra of the two quasars in each pair and the identification of the lens galaxies, we conclude that the objects are gravitational lenses. The lenses are complicated; in both systems there are several galaxies in the fields very close to the quasars, in addition to the lens galaxies themselves. The lens modeling implies that these nearby galaxies contribute significantly to the lens potentials. On larger scales, we have detected an enhancement in the galaxy density near SDSS J100128.61+502756.9. The number of lenses with image separation of ~3'' in the SDSS already exceeds the prediction of simple theoretical models based on the standard Lambda-dominated cosmology and observed velocity function of galaxies., Comment: 24 pages, 9 figures, accepted for publication in ApJ

We recently reported the discovery of a new galaxy type, ultra-compact dwarf (UCD) galaxies, in both the Fornax and Virgo clusters. Here we present new detections of a larger population of UCDs in the Fornax Cluster, as well as the first detections of UCDs in two galaxy groups. We extended our original survey of the Fornax Cluster 1 magnitude fainter, finding a further 46 new compact objects. This means that UCDs outnumber normal galaxies in the central region of the Fornax Cluster. We used this large UCD sample to test the tidal stripping model: simulations indicate that only about half of the UCD population may have formed by disruption of the observed population of nucleated dwarf galaxies. As the UCDs are strongly clustered towards the cluster centre, we conclude that the remaining UCDs must be associated with the much earlier assembly of the central galaxy.

We review the evidence that the ultra-compact dwarf (UCD) galaxies we recently discovered in the Fornax Cluster form a new, previously unknown class of galaxies and we discuss possible scenarios for their formation. We then present recent results that UCDs are also present in the Virgo Cluster, and that there is a much larger than expected population of fainter UCDs in the Fornax Cluster. The size and properties of this population may lead us to revise our original ‘galaxy threshing’ hypothesis for the formation of UCDs.

We have identified galaxies near two quasars which are at the redshift of damped Lyman-alpha (DLA) systems in the UV spectra of the quasars. Both galaxies are actively forming stars. One galaxy has a luminosity close to the break in the local galaxy luminosity function, L*, the other is significantly fainter than L* and appears to be interacting with a nearby companion. Despite the strong selection effects favoring spectroscopic identification of the most luminous DLA galaxies, many of the spectroscopically-identified DLA galaxies in the literature are sub-L*, suggesting that the majority of the DLA population is probably sub-L*, in contrast to MgII absorbers at similar redshifts whose mean luminosity is close to L*., Comment: 9 pages, to appear in AJ, November 2003 issue

We present a new sample of 35 quasars selected from the FIRST radio survey and the Deeprange I-band survey (Postman et al. 1998, 2002). A comparison with the FIRST Bright Quasar survey samples reveals that this I-band selected sample is redder by 0.25-0.5 mag in B-R, and that the color difference is not explained by the higher mean redshift of this sample but must be intrinsic. Our small sample contains five quasars with unusually red colors, including three that appear very heavily reddened. Our data are fitted well with normal blue quasar spectra attenuated by more than 2.5 magnitudes of extinction in the I-band. The red quasars are only seen at low redshifts (z, 19 pages, 12 figures; submitted to the Astronomical Journal

We present the second gravitationally lensed quasar discovered during the course of a Hubble Space Telescope Space Telescope Imaging Spectrograph snapshot survey for small-separation gravitational lenses. CTQ 327 is a double quasar with an image separation of 122 and a g-band flux ratio of roughly 5 to 1. Spectra reveal both components to be z = 1.37 quasars, and the lensing galaxy is clearly visible after point-spread function subtraction of the two quasar components. The light profile of the lensing galaxy is well modeled by an r1/4 law, indicative of an early-type elliptical galaxy. An estimate of the lens galaxy redshift is z ~ 0.4–0.6, based on the Faber-Jackson relationship and photometric considerations, although values outside this range are still consistent with the present data. Resolved spectra of the two quasars show similar, but not identical, continuum and emission-line features: component A exhibits weaker emission lines with respect to the continuum than does component B, and there is evidence of intrinsic differences in the emission-line profiles between the two components. Optical monitoring of the quasar pair also shows a change in the g-band flux ratio of 0.14 mag over a 3 month period. These spectral and photometric differences may be due to microlensing fluctuations from stars in the lensing galaxy, intrinsic quasar variability coupled with the system's differential time delay, or some combination of the two. The observed variability makes CTQ 327 an attractive target for future flux monitoring, aimed at time-delay or microlensing studies.

We have discovered a new type of galaxy in the Fornax Cluster: ``ultra-compact'' dwarfs (UCDs). The UCDs are unresolved in ground-based imaging and have spectra typical of old stellar systems. Although the UCDs resemble overgrown globular clusters, based on VLT UVES echelle spectroscopy, they appear to be dynamically distinct systems with higher internal velocity dispersions and M/L ratios for a given luminosity than Milky Way or M31 globulars. Our preferred explanation for their origin is that they are the remnant nuclei of dwarf elliptical galaxies which have been tidally stripped, or ``threshed'' by repeated encounters with the central cluster galaxy, NGC1399. If correct, then tidal stripping of nucleated dwarfs to form UCDs may, over a Hubble time, be an important source of the plentiful globular cluster population in the halo of NGC1399, and, by implication, other cD galaxies. In this picture, the dwarf elliptical halo contents, up to 99% of the original dwarf luminosity, contribute a significant fraction of the populations of intergalactic stars, globulars, and gas in galaxy clusters.

We report the correct classification of an overlooked Fanaroff-Riley class II radio-loud quasar with broad absorption lines, only the second such object so identified. The rare properties of this quasar, LBQS 1138-0126, are twice overlooked. First LBQS 1138-0126 was found in the Large Bright Quasar Survey but only noted as a possible broad absorption line quasar without additional follow-up. Later LBQS 1138-0126 was rediscovered and classified as a radio-loud broad absorption line quasar but not recognized as an FR II radio source. We describe the radio, absorption line, and optical polarization properties of LBQS 1138-0126 and place it in context with respect to related quasars. In particular, spectropolarimetry shows that LBQS 1138-0126 has high continuum polarization increasing from 3% in the red (rest-frame 2400 Angstroms) to over 4% in the blue (rest-frame 1650 Ansgtroms), essentially confirming the intrinsic nature of the absorption. The polarization position angle rotates from about -30 degrees in the red to about 0 degrees in the blue; the radio lobe position angle is 52 degrees for comparison. LBQS 1138-0126 is additionally notable for being one of the most radio-loud broad absorption line quasars, and for having low-ionization broad absorption lines as well.

In an ongoing infrared imaging survey of quasars at Keck Observatory, we have discovered that the z=1.285 quasar SDSS J233646.2-010732.6 comprises two point sources with a separation of 1.67". Resolved spectra show that one component is a standard quasar with a blue continuum and broad emission lines; the other is a broad absorption line (BAL) quasar, specifically, a BAL QSO with prominent absorption from MgII and metastable FeII, making it a member of the ``FeLoBAL'' class. The number of known FeLoBALs has recently grown dramatically from a single example to more than a dozen, including a gravitationally lensed example and the binary member presented here, suggesting that this formerly rare object may be fairly common. Additionally, the presence of this BAL quasar in a relatively small separation binary adds to the growing evidence that the BAL phenomenon is not due to viewing a normal quasar at a specific orientation, but rather that it is an evolutionary phase in the life of many, if not all, quasars, and is particularly associated with conditions found in interacting systems.

We report the discovery of a z=2.65 low-ionization iron broad absorption line quasar, FIRST J100424.9+122922, which is gravitationally-lensed by a galaxy at z~0.95. The object was discovered as part of a program to find very red quasars by matching the FIRST radio survey with the 2-MASS near-infrared survey. J100424.9+122922 is the second lensed system to be found in this program, suggesting that many gravitational lenses are probably missed from conventional optical quasar surveys. We have made a simple lens model and a rough estimate of the reddening in the immediate environment of the quasar which suggests that the quasar is intrinsically very luminous and is accreting at close to the Eddington limit of its ~10^9 M_sun black hole. The lensing galaxy has a small amount of dust which is responsible for some excess reddening observed in the fainter image of the quasar, but is otherwise a fairly typical massive elliptical galaxy. We model the selection effects working against the detection of red quasars in both lensed and unlensed samples. We show that these selection effects are very effective at removing even lightly-reddened high redshift quasars from magnitude-limited samples, whether they are lensed or not. This suggests that the red quasar population in general could be very large, and in particular the class of iron broad absorption line quasars of which J100424.9+122922 is a member may be much larger than their rarity in magnitude-limited samples would suggest.

A Keck echelle spectrum of the quasar FBQS 0840+3633 reveals outflowing gas that gives rise to blueshifted absorption lines of many low-ionization species. The gas covers a range of velocities from -700 to -3500 km s-1, with two main components centered at -900 and -2800 km s-1. The physical conditions in the two main velocity components are found to be significantly different and can be attributed to a difference of a factor of ~100 in the distance from the central continuum source. The low-velocity gas shows absorption lines from excited states with relative strengths that indicate a low density. The level populations of low-lying Ni II, Si II, and Fe II states cannot be explained with a model based on collisional excitation and a single electron density. The lines of Si II provide an upper limit on the electron density of ne < 500 cm-3, and another excitation mechanism must be responsible for the observed excitation of Fe II and Ni II. Assuming that this mechanism is UV fluorescence leads to an estimate of the distance between the low-velocity gas and the active nucleus of ~230 pc. Absorption lines from excited states formed in the high-velocity gas indicate a much higher density. This gas gives rise to Fe III and strong Al III absorption, which indicates that it contains the hydrogen ionization front on our line of sight to the active nucleus. The observed Fe III and Al III column densities and the absence of detectable absorption from the He I 23S state allow us to derive an estimate of the typical distance between the high-velocity gas and the active nucleus of ~1 pc.

This paper presents an analysis of a Keck HIRES spectrum of the QSO FIRST J121442.3+280329, covering the rest wavelength range from 2300 to 3500 A. The line of sight toward this quasar (QSO) contains an outflow giving rise to many blueshifted absorption lines. The outflow consists of material with a continuous range of velocities from -1200 to -2800 km s-1. Significant substructure is present in the absorption line profiles. The spectrum is dominated by absorption lines of Mg II and the singly ionized iron group elements Fe II, Cr II, and Mn II, including absorption lines from excited levels with energies above 30,000 cm-1 (~4 eV).We derive constraints on the physical conditions in the outflow by fitting a model to the observed spectrum that simultaneously optimizes the values for the column densities of all species, the excitation temperature, the shape of the unabsorbed continuum, and the covering factor. By comparing these constraints with ionization models, we conclude that the ionization parameter, density, and column density of the outflow is characterized by -2.0 < log U < -0.7, 7.5 < log nH < 9.5, and 21.4 < log NH < 22.2. These values place the absorbing outflow at a distance between 1 and 30 pc from the QSO core.

In a survey of quasar candidates selected by matching the FIRST and 2MASS catalogs, we have found two extraordinarily red quasars. FIRST J013435.7-093102 is a 1 Jy source at z=2.216 and has B-K > 10, while FIRST J073820.1+275045 is a 2.5 mJy source at z=1.985 with B-K = 8.4. FIRST J073820.1+275045 has strong absorption lines of MgII and CIV in the rest frame of the quasar and is highly polarized in the rest frame ultraviolet, strongly favoring the interpretation that its red spectral energy distribution is caused by dust reddening local to the quasar. FIRST J073820.1+275045 is thus one of the few low radio-luminosity, highly dust-reddened quasars known. The available observational evidence for FIRST J013435.7-093102 leads us to conclude that it too is reddened by dust. We show that FIRST J013435.7-093102 is gravitationally lensed, increasing the number of known lensed, extremely dust-reddened quasars to at least three, including MG0414-0534 and PKS1830-211. We discuss the implications of whether these objects are reddened by dust in the host or lensing galaxies. If reddened by their local environment, then we estimate that between 10 and 20% of the radio-loud quasar population is reddened by dust in the host galaxy. The discovery of FIRST J073820.1+275045 and objects now emerging from X-ray surveys suggests the existence of an analogous radio-quiet red quasar population. Such objects will be entirely missed by standard radio or optical quasar surveys. If dust in the lensing galaxies is primarily responsible for the extreme redness of the lensed quasars, then an untold number of gravitationally lensed quasars are being overlooked., AASTEX 24 pp., 7 figs; accepted by ApJ. See also the preprint astro-ph/0107435 by Winn et al., who independently discovered that J013435.7-093102 is gravitationally lensed

We present g 0 and z 0 aperture photometry for 96 Galactic Globular Clusters, making this thelargest homogeneous catalog of photometry for these objects in the SDSS filter system. For asubset of 56 clusters we also provide photometry in r 0 and i . We carry out comparisons withprevious photometry as well as with the SDSS dataset. The data will be useful for a series ofapplications in Galactic and extragalactic astrophysics. Future papers will analyse the colour-metallicity relation, colour-magnitude diagrams, and structural parameters. The compilationof results based on this dataset will be collected in the Galactic Globular Cluster Catalog(G2C2).Key words: Galactic Globular Clusters 1 INTRODUCTIONGlobular clusters (hereafter GCs) formed during the earliestepisodes of star formation in galaxies. They are found in all but thesmallest dwarf galaxies, with massive galaxies hosting systems ofhundreds or thousands of clusters. The properties of globular clus-ters appear to be very homogeneous from one galaxy to the other(in terms of colour, luminosity distribution, etc.) and this impliesthat the formation of these objects has been intimately related tothe assembly of their parent galaxies (e.g., Harris 1991). Globu-lar clusters are living fossils of the Universe at high redshift (theirmass is similar to the Jeans mass at the epoch of recombination) andtherefore give a snapshot of conditions as prevailed at early epochs(see West et al. 2004; Brodie & Strader 2006 for reviews). The in-tegrated properties of globular clusters therefore provide us withinformation on the earliest stages of galaxy formation; the high in-trinsic luminosities of clusters means that they can be studied in de

KA1858+4850 is a narrow-line Seyfert 1 galaxy at redshift 0.078 and is among the brightest active galaxies monitored by the Kepler mission. We have carried out a reverberation mapping campaign designed to measure the broad-line region size and estimate the mass of the black hole in this galaxy. We obtained 74 epochs of spectroscopic data using the Kast Spectrograph at the Lick 3-m telescope from February to November of 2012, and obtained complementary V-band images from five other ground-based telescopes. We measured the H-beta light curve lag with respect to the V-band continuum light curve using both cross-correlation techniques (CCF) and continuum light curve variability modeling with the JAVELIN method, and found rest-frame lags of lag_CCF = 13.53 (+2.03, -2.32) days and lag_JAVELIN = 13.15 (+1.08, -1.00) days. The H-beta root-mean-square line profile has a width of sigma_line = 770 +/- 49 km/s. Combining these two results and assuming a virial scale factor of f = 5.13, we obtained a virial estimate of M_BH = 8.06 (+1.59, -1.72) x 10^6 M_sun for the mass of the central black hole and an Eddington ratio of L/L_Edd ~ 0.2. We also obtained consistent but slightly shorter emission-line lags with respect to the Kepler light curve. Thanks to the Kepler mission, the light curve of KA1858+4850 has among the highest cadences and signal-to-noise ratios ever measured for an active galactic nucleus; thus, our black hole mass measurement will serve as a reference point for relations between black hole mass and continuum variability characteristics in active galactic nuclei.

The origin of the closest compact elliptical galaxy (cE) M32 is a longstanding problem of galaxy formation in the Local Group. Our N-body/SPH simulations suggest a new scenario in which the strong tidal field of M31 can transform a spiral galaxy into a compact elliptical. As a low luminosity spiral galaxy plunges into the central region of M31, most of the outer stellar and gaseous components of its disk are dramatically stripped due to M31's tidal field The central bulge component, on the other hand, is just weakly influenced by the tidal field owing to its compact configuration, and retains its morphology. M31's strong tidal field also induces rapid gas transfer to the central region, triggers a nuclear starburst, and consequently forms the central high density and more metal-rich stellar populations with relatively young ages. Thus, in this scenario, M32 was previously the bulge of a spiral tidally interacting with M31 several Gyr ago. Furthermore, we suggest cEs like M32 are rare, the result of both the rather narrow parameter space for tidal interactions which morphologically transform spirals into cEs and the very short time scale ($

We present detailed analyses of the absorption spectrum seen in QSO 2359-1241 (NVSS J235953-124148). Keck HIRES data reveal absorption from twenty transitions arising from: He I, Mg I, Mg II, Ca II, and Fe II. HST data show broad absorption lines (BALs) from Al III 1857, C IV 1549, Si IV 1397, and N V 1240. Absorption from excited Fe II states constrains the temperature of the absorber to 2000K < T < 10,000K and puts a lower limit of 10^5 cm^{-3} on the electron number density. Saturation diagnostics show that the real column densities of He I and Fe II can be determined, allowing to derive meaningful constraints on the ionization equilibrium and abundances in the flow. The ionization parameter is constrained by the iron, helium and magnesium data to -3.0 < log(U) < -2.5 and the observed column densities can be reproduced without assuming departure from solar abundances. From comparison of the He I and Fe II absorption features we infer that the outflow seen in QSO 2359-1241 is not shielded by a hydrogen ionization front and therefore that the existence of low-ionization species in the outflow (e.g., Mg II, Al III, Fe II) does not necessitate the existence of such a front. We find that the velocity width of the absorption systematically increases as a function of ionization and to a lesser extent with abundance. Complementary analyses of the radio and polarization properties of the object are discussed in a companion paper (Brotherton et al. 2000).

We present observations of SDSSp J104433.04--012502.2, a luminous quasar at z=5.80 discovered from Sloan Digital Sky Survey (SDSS) multicolor imaging data. This object was selected as an i'-band dropout object, with i*=21.8 +/- 0.2, z*=19.2 +/- 0.1. It has an absolute magnitude M1450 = -27.2 (H_0 =50 km/s/Mpc, q0 = 0.5). The spectrum shows a strong and broad Ly alpha emission line, strong Ly alpha forest absorption lines with a mean continuum decrement D_A = 0.91, and a Lyman Limit System at z=5.72. The spectrum also shows strong OI and SiIV emission lines similar to those of quasars at z

We have obtained V- and I-band photometry for 1886 stars down to I = 27 and V = 28 in the field of the dwarf irregular galaxy WLM, using deep Space Telescope Imaging Spectrograph (STIS) CL- and LP-band images taken in the parallel mode with the Hubble Space Telescope. The photometry is used to study the horizontal branch identified in WLM. The horizontal branch, extending blueward from the red giant clump, is an unambiguous signature of an old population. We demonstrate that it is possible to reach the horizontal branch of an old population at a distance of 1 Mpc using STIS, with relatively short exposure times. From the VI color-magnitude diagram, we obtain an accurate distance modulus (m - M)0 = 24.95 ? 0.13 for WLM by using the V magnitude of the horizontal branch, and by adopting E(V-I) = 0.03. The implications are that (1) WLM formed stars at high redshift and (2) the old population of WLM can be representative of a protogalactic fragment, related to those accreted to form the Milky Way halo.

In a spectroscopic follow-up to the VLA FIRST survey, the FIRST Bright Quasar Survey (FBQS) has found 29 radio-selected broad absorption line (BAL) quasars. This sample provides the first opportunity to study the properties of radio-selected BAL quasars. Contrary to most previous studies, we establish that a significant population of radio-loud BAL quasars exists. Radio-selected BAL quasars display compact radio morphologies and possess both steep and flat radio spectra. Quasars with low-ionization BALs have a color distribution redder than that of the FBQS sample as a whole. The frequency of BAL quasars in the FBQS is significantly greater, perhaps by as much as a factor of two, than that inferred from optically selected samples. The frequency of BAL quasars appears to have a complex dependence on radio-loudness. The properties of this sample appear inconsistent with simple unified models in which BAL quasars constitute a subset of quasars seen edge-on.

In the course of a Cycle 8 snapshot survey, we have discovered that the z=1.565 quasar HE 0512-3329 is a double with image separation 0.644", almost certainly due to gravitational lensing. The two components differ in brightness by only 0.4 magnitudes and a high signal-to-noise ground-based composite optical spectrum shows no trace of any stellar features at zero redshift, essentially ruling out the possibility that one of the two components is an ordinary Galactic star. The optical spectrum shows strong absorption features of MgII, MgI, FeII, FeI, and CaI, all at an identical intervening redshift of z=0.9313, probably due to the lensing object. The strength of the MgII and the presence of the other low ionization absorption features is strong evidence for a damped Lyman alpha system, likely the disk of a spiral galaxy. Point spread function fitting to remove the two quasar components from the STIS image leads to a tentative detection of a third object which may be the nucleus of the lensing galaxy. The brighter component is significantly redder than the fainter, due to either differential extinction or microlensing., AASTEX preprint format, 11 pages, 3 figures; accepted by the Astronomical Journal; replaced with revised, accepted version

We have used the VLA FIRST survey and the APM catalog of the POSS-I plates as the basis for constructing a new radio-selected sample of optically bright quasars. This is the first radio-selected sample that is competitive in size with current optically selected quasar surveys. Using only two basic criteria, radio-optical positional coincidence and optical morphology, quasars and BL Lacs can be identified with 60% selection efficiency; the efficiency increases to 70% for objects fainter than magnitude 17. We show that a more sophisticated selection scheme can predict with better than 85% reliability which candidates will turn out to be quasars. This paper presents the second installment of the FIRST Bright Quasar Survey with a catalog of 636 quasars distributed over 2682 square degrees. The quasar sample is characterized and all spectra are displayed. The FBQS detects both radio-loud and radio-quiet quasars out to a redshift z>3. We find a large population of objects of intermediate radio-loudness; there is no evidence in our sample for a bimodal distribution of radio characteristics. The sample includes ~29 broad absorption line quasars, both high and low ionization, and a number of new objects with remarkable optical spectra., 41 pages plus 39 gifs which contain all quasar spectra. Accepted for publication in the Astrophysical Journal Supplement Series

We find that the depth and shape of the broad absorption lines (BALs) in BALQSO 1603+3002 are determined largely by the fraction of the emitting source which is covered by the BAL flow. In addition, the observed depth of the BALs is poorly correlated with their real optical depth. The implication of this result is that abundance studies based on direct extraction of column densities from the depth of the absorption troughs are unreliable. Our conclusion is based on analysis of unblended absorption features of two lines from the same ion (in this case the Si IV doublet), which allows unambiguous separation of covering factor and optical depth effects. The complex morphology of the covering factor as a function of velocity suggests that the BALs are produced by several physically separated outflows. The covering factor is ion dependent in both depth and velocity width. We also find evidence that in BALQSO 1603+3002 the flow does not cover the broad emission line region.

Although the existence of a faint background of starlight in the core of the Coma cluster has been well established (1,2), its origin is uncertain. This vast sea of stars could have formed outside the galaxies, using gas left over from the time of the cluster's birth. Alternatively, it might be the accumulated debris generated by interactions between the galaxies over the lifetime of the cluster (3). Here we report the discovery of three large, low surface brightness features in the Coma cluster; the most spectacular is a plume-like structure, 130 kpc long, in the cluster's heart. These structures will disperse over the next one to two billion years, thereby enhancing the general background light. If this epoch is typical, we argue that a significant fraction -- perhaps even most -- of the intracluster light results from a steady accumulation of tidal debris generated during galaxy-galaxy and galaxy-cluster interactions.

We describe a search for compact dwarf galaxies in the Fornax cluster using the FLAIR spectrograph on the UK Schmidt Telescope. We measured radial velocities of 453 compact galaxies brighter than Bt=17.3 and found seven new compact dwarf cluster members that were not classified in previous surveys as members of the cluster. These are amongst the most compact, high surface brightness dwarf galaxies known. The inclusion of these galaxies in the cluster does not change the total luminosity function significantly but they are important because of their extreme nature; one in particular appears to be a high (normal) surface brightness dwarf spiral. Three of the new dwarfs have strong emission lines and appear to be blue compact dwarfs (BCDs), doubling the number of confirmed BCDs in the cluster. We also determined that none of the compact dwarf elliptical (M32-like) candidates are in the cluster, down to an absolute magnitude Mb=-13.2. We have investigated the claim of Irwin et al. (1990) that there is no strong relation between surface brightness and magnitude for the cluster members and find some support for this for the brighter galaxies (Bt, Submitted to Monthly Notices of the Royal Astronomical Society, 5 pages; a LaTeX file (uses mn.sty) and 5 eps figures

The diameter - velocity dispersion relation in B, V, and K for three early-type galaxies in the Leo I (M96) group is derived from published photometry and kinematic data. The relations in all three colors have slopes which agree well with those for the Coma cluster. The RMS scatter of the Leo I galaxies in each color is extremely small, consistent with the group's compactness. These relations yield estimates of the Coma-Leo I distance ratio of 9.01 +/- 0.51, 8.77 +/- 0.43, and 8.82 +/- 0.31, respectively, with a weighted mean of 8.84 +/- 0.23. The general agreement among the three colors indicates that the early-type galaxies in Leo I and Coma have similar stellar populations. The Coma-Leo I distance ratio coupled with estimates of the absolute distance to the Leo I group allows the Hubble constant to be determined, free of the uncertainties which arise when working with the Virgo cluster. Several high quality distance estimates are available from a variety of techniques: Cepheids in M96 (Tanvir et al. 1995) and M95 (Graham et al. 1997), surface brightness fluctuations (Tonry et al. 1997), planetary nebulae luminosity functions (Ciardullo et al. 1993), and the luminosity of the red giant branch tip (Sakai, Freedman, & Madore 1996). Adopting a cosmic recession velocity of the Coma cluster in the microwave background frame of 7200 +/- 300 km/s, these distance estimates lead to values of the Hubble constant ranging from 70 to 81 km/s/Mpc, with an unweighted mean of 75 +/- 6 km/s/Mpc., To appear in New Astronomy; 15 pages including 3 figures and 2 tables

We present a catalog of 138,665 radio sources derived from the initial 1550 deg2 of the FIRST survey. The survey parameters are reviewed, and a map depicting the coverage for the first two observing sessions is presented. We then describe in detail our algorithm for radio source detection and parameterization, as well as our procedures for constructing the final catalog. The results of extensive tests for astrometric and photometric accuracy, as well as for uncertainties in source extent and morphological characterization, are presented. Source positions are all good to better than 1'', and the flux density scale is accurate to 5%; our elliptical Gaussian fitting procedure is shown both to provide a high-fidelity representation of source morphology for most objects and to characterize correctly bright sources extended on scales down to ~ the synthesized beam size of 54. We use the catalog to construct a log N-log S relation for 20 cm radio sources over four decades of flux density, finding excellent agreement with previous determinations from smaller surveys. As one example of the catalog's utility, we present comparisons with the Guide Star Catalog, the IRAS Faint Source catalog, and the ROSAT WGA catalog, identifying radio counterparts to thousands of the objects. Complete instructions for access to this FIRST catalog and subsequent updates thereto are provided.

HE0512–3329 is a gravitationally-lensed double QSO with damped Ly $\alpha$ systems observed at $z=0.931$ in front of both QSO images (DLA A and B). We have obtained spatially resolved HST STIS and optical VLT UVES spectra of both QSOs in order to study differences in the metal abundances across the lines of sight. We detect substantial differences, of roughly 0.5 dex, in both [Mn/H] and [Fe/H], on a transverse scale of 5 $h^{-1}$ kpc. Differential dust depletion appears as the most plausible explanation.

We report the results of a new 60 ks Chandra X-ray Observatory Advanced CCD Imaging Spectrometer S-array (ACIS-S) observation of the reddened, radio-selected, highly polarized `FeLoBAL' quasar FIRST J1556+3517. We investigated a number of models of varied sophistication to fit the 531-photon spectrum. These models ranged from simple power laws to power laws absorbed by hydrogen gas in differing ionization states and degrees of partial covering. Preferred fits indicate that the intrinsic X-ray flux is consistent with that expected for quasars of similarly high luminosity, i.e., an intrinsic, dereddened and unabsorbed optical to X-ray spectral index of -1.7. We cannot tightly constrain the intrinsic X-ray power-law slope, but find indications that it is flat (photon index Gamma = 1.7 or flatter at a >99% confidence for a neutral hydrogen absorber model). Absorption is present, with a column density a few times 10^23 cm^-2, with both partially ionized models and partially covering neutral hydrogen models providing good fits. We present several lines of argument that suggest the fraction of X-ray emissions associated with the radio jet is not large. We combine our Chandra data with observations from the literature to construct the spectral energy distribution of FIRST J1556+3517 from radio to X-ray energies. We make corrections for Doppler beaming for the pole-on radio jet, optical dust reddening, and X-ray absorption, in order to recover a probable intrinsic spectrum. The quasar FIRST J1556+3517 seems to be an intrinsically normal radio-quiet quasar with a reddened optical/UV spectrum, a Doppler-boosted but intrinsically weak radio jet, and an X-ray absorber not dissimilar from that of other broad absorption line quasars., to be published in MNRAS

Results of a spectroscopic search for M32-like compact elliptical galaxies in the Fornax cluster are presented. None were found, which suggests that these objects represent the low luminosity end of the giant elliptical luminosity function, rather than being formed by tidal stripping. The sample is used to investigate the large-scale distribution of bright ellipticals.