295 research outputs found
Blue outliers among intermediate redshift quasars
[Oiii]{\lambda}{\lambda}4959,5007 "blue outliers" -- that are suggestive of
outflows in the narrow line region of quasars -- appear to be much more common
at intermediate z (high luminosity) than at low z. About 40% of quasars in a
Hamburg ESO intermediate-z sample of 52 sources qualify as blue outliers (i.e.,
quasars with [OIII] {\lambda}{\lambda}4959,5007 lines showing large systematic
blueshifts with respect to rest frame). We discuss major findings on what has
become an intriguing field in active galactic nuclei research and stress the
relevance of blue outliers to feedback and host galaxy evolution.Comment: Accepted for publication in Astrophysics and Space Science, Special
Issue on Line Shifts in Astrophysics and Laboratory Plasm
HE0359-3959: an extremely radiating quasar
We present a multiwavelength spectral study of the quasar HE0359-3959, which
has been identified as an extreme radiating source at intermediate redshift
(z=1.5209). Along the spectral range, the different ionic species give
information about the substructures in the broad line region. The presence of a
powerful outflow with an extreme blueshifted velocity of -6000500 km
s is shown in the CIV{\lambda}1549 emission line. A prominent
blueshifted component is also associated with the 1900{\AA} blend, resembling
the one observed in CIV{\lambda}1549. We detect a strong contribution of very
the low-ionization lines, FeII and Near-Infrared CaII triplet. We find that the
physical conditions for the low, intermediate and high-ionization emission
lines are different, which indicate that the emission lines are emitted in
different zones of the broad line region. The asymmetries shown by the profiles
reveal different forces over emitter zones. The high-ionization region is
strongly dominated by radiation forces, which also affect the low and
intermediate-ionization emitter region, commonly governed by virial motions.
These results support the idea that highly radiating sources host a slim disk.Comment: 10 pages, 3 figure
A revised view of the Canis Major stellar overdensity with DECam and Gaia: new evidence of a stellar warp of blue stars
We present DECam imaging combined with Gaia DR2 data to study the Canis Major
overdensity. The presence of the so-called Blue Plume stars in a low-pollution
area of the color-magnitude diagram allows us to derive the distance and proper
motions of this stellar feature along the line of sight of its hypothetical
core. The stellar overdensity extends on a large area of the sky at low
Galactic latitudes, below the plane, and between 230. According to the orbit derived for Canis Major, it presents an
on-plane rotation around the Milky Way. Moreover, additional overdensities of
Blue Plume stars are found around the plane and across the Galaxy, proving that
these objects are not only associated with that structure. The spatial
distribution of these stars, derived using Gaia astrometric data, confirms that
the detection of the Canis Major overdensity results more from the warped
structure of the Milky Way disk than from the accretion of a dwarf galaxy.Comment: 11 pages, 9 figures, accepted for publication in MNRA
Tails and streams around the Galactic globular clusters NGC 1851, NGC 1904, NGC 2298 and NGC 2808
We present Dark Energy Camera imaging for the peculiar Galactic globular clusters NGCâ1851, NGCâ1904 (Mâ79), NGCâ2298 and NGCâ2808. Our deep photometry reveals that all the clusters have an important contribution of stars beyond their King tidal radii and present tails with different morphologies. We have also explored the surroundings of the clusters where the presence of the Canis Major overdensity and/or the low Galactic latitude Monoceros ring at dâ ⌠8âkpc is evident. A second stellar system is found at dâ ⌠17âkpc and spans at least 18âdeg Ă 15âdeg in the sky. As one of the possible scenarios to explain that feature, we propose that the unveiled system is part of Monoceros explained as a density wave moving towards the outer Milky Way. Alternatively, the unveiled system might be connected with other known halo substructures or associated with the progenitor dwarf galaxy of NGCâ1851 and NGCâ1904, which are widely considered accreted globular clusters
Toward a clinical practice guide in pharmacogenomics testing for functional polymorphisms of drug-metabolizing enzymes. Gene/drug pairs and barriers perceived in Spain
The development of clinica lpractice recommendations or
guidelines for the clinical use of biomarkers is an issue of great importance withr regard to adverse drug reactions.The poten-tial of pharmacogenomicbiomarkers has been extensively investigated in recent years.However,several barriers to implementing the use of pharmacogenomics testing exist.We conducted a survey among members of the Spanish Societies of Pharmacology and Clinical Pharmacology to obtain information about the perception of such barriers and to compare the perceptions of participants about the relative importance of majorgene/drug pairs.Of 11 potential barriers,the highest importance was attributed to lack of institutional support for pharmacogenomic stesting,and to the issues related to the lack of guidelines.Of the proposed gene/drug pairs the highest importance was assigned to HLA-B/abacavir, UGT1A1/irinotecan, and CYP2D6/tamoxifen.In this perspective article,we compare the relative importance of 29 gene/drugpairs in the Spanish study with that of the same pairs in the American Society for Clinical Pharmacology and Therapeutic sstudy,and we provide suggestions and areas of focus to develop a guide for clinical practice in pharmacogenomics testingThe work in the authorâs laboratory is financed by Grants
PS09/00943, PS09/00469, RETICS RIRAAF RD07/0064/0016,
and CIBERehd from Instituto de Salud CarlosIII,Madrid,
Spain, and by Grants GR10068 from Junta de Extremadura,
Spain. Financed in part with FEDER funds from the European
Unio
A Main Sequence For Quasars
The 4D eigenvector 1 parameter space defined by Sulentic et al. may be seen as a surrogate H-R diagram for quasars. As in the stellar H-R diagram, a source sequence can be easily identified. In the case of quasars, the main sequence appears to be mainly driven by Eddington ratio. A transition Eddington ratio may in part explain the striking observational differences between quasars at opposite ends of the main sequence. The eigenvector-1 approach opens the door towards properly contextualized models of quasar physics, geometry and kinematics. We review some of the progress that has been made over the past 15 years, and point out still unsolved issues
3C 57 as an Atypical Radio-Loud Quasar: Implications for the Radio-Loud/Radio-Quiet Dichotomy
Lobe-dominated radio-loud (LD RL) quasars occupy a restricted domain in the
4D Eigenvector 1 (4DE1) parameter space which implies restricted
geometry/physics/kinematics for this subclass compared to the radio-quiet (RQ)
majority of quasars. We discuss how this restricted domain for the LD RL parent
population supports the notion for a RQ-RL dichotomy among Type 1 sources. 3C
57 is an atypical RL quasar that shows both uncertain radio morphology and
falls in a region of 4DE1 space where RL quasars are rare.
We present new radio flux and optical spectroscopic measures designed to
verify its atypical optical/UV spectroscopic behaviour and clarify its radio
structure. The former data confirms that 3C 57 falls off the 4DE1 quasar "main
sequence" with both extreme optical FeII emission (R_{FeII} ~ 1) and a large
CIV 1549 profile blueshift (~ -1500 km/s). These parameter values are typical
of extreme Population A sources which are almost always RQ. New radio measures
show no evidence for flux change over a 50+ year timescale consistent with
compact steep-spectrum (CSS or young LD) over core-dominated morphology. In the
4DE1 context where LD RL are usually low L/L_{Edd} quasars we suggest that 3C
57 is an evolved RL quasar (i.e. large Black Hole mass) undergoing a major
accretion event leading to a rejuvenation reflected by strong FeII emission,
perhaps indicating significant heavy metal enrichment, high bolometric
luminosity for a low redshift source and resultant unusually high Eddington
ratio giving rise to the atypical CIV 1549.Comment: Accepted for publication in MNRAS; 10 pages, 6 figures, 4 table
Reading Between the (Spectral) Lines: Magellan/IMACS spectroscopy of the Ultra-faint Dwarf Galaxies Eridanus IV and Centaurus I
We present a spectroscopic analysis of Eridanus IV (Eri IV) and Centaurus I
(Cen I), two ultra-faint dwarf galaxies of the Milky Way. Using IMACS/Magellan
spectroscopy, we identify 28 member stars of Eri IV and 34 member stars of Cen
I. For Eri IV, we measure a systemic velocity of and velocity dispersion . Additionally, we measure the
metallicities of 16 member stars of Eri IV. We find a metallicity of
and resolve a dispersion of
. The mean metallicity is marginally
lower than all other known ultra-faint dwarf galaxies, making it one of the
most metal-poor galaxies discovered thus far. Eri IV also has a somewhat
unusual right-skewed metallicity distribution. For Cen I, we find a velocity
and velocity dispersion . We measure the metallicities of 27
member stars of Cen I, and find a mean metallicity and metallicity dispersion . We calculate the systemic proper motion, orbit, and the
astrophysical J-factor for each system, the latter of which indicates that Eri
IV is a good target for indirect dark matter detection. We also find no strong
evidence for tidal stripping of Cen I or Eri IV. Overall, our measurements
confirm that Eri IV and Cen I are dark matter-dominated galaxies with
properties largely consistent with other known ultra-faint dwarf galaxies. The
low metallicity, right-skewed metallicity distribution, and high J-factor make
Eri IV an especially interesting candidate for further followup.Comment: 25 pages, 11 figures, submitted to AAS journal
Six More Ultra-Faint Milky Way Companions Discovered in the DECam Local Volume Exploration Survey
We report the discovery of six ultra-faint Milky Way satellites discovered
through matched-filter searches conducted using Dark Energy Camera (DECam) data
processed as part of the second data release of the DECam Local Volume
Exploration (DELVE) survey. Leveraging deep Gemini/GMOS-N imaging (for four
candidates) as well as follow-up DECam imaging (for two candidates), we
characterize the morphologies and stellar populations of these systems. We find
that these candidates all share faint absolute magnitudes (
mag) and old, metal-poor stellar populations ( Gyr, [Fe/H]
dex). Three of these systems are more extended ( pc), while the
other three are compact ( pc). From these properties, we infer
that the former three systems (Bo\"{o}tes V, Leo Minor I, and Virgo II) are
consistent with ultra-faint dwarf galaxy classifications, whereas the latter
three (DELVE 3, DELVE 4, and DELVE 5) are likely ultra-faint star clusters.
Using data from the Gaia satellite, we confidently measure the proper motion of
Bo\"{o}tes V, Leo Minor I, and DELVE 4, and tentatively detect a proper motion
signal from DELVE 3 and DELVE 5; no signal is detected for Virgo II. We use
these measurements to explore possible associations between the
newly-discovered systems and the Sagittarius dwarf spheroidal, the Magellanic
Clouds, and the Vast Polar Structure, finding several plausible associations.
Our results offer a preview of the numerous ultra-faint stellar systems that
will soon be discovered by the Vera C. Rubin Observatory and highlight the
challenges of classifying the faintest stellar systems.Comment: 30 pages, 12 Figures (including Appendix). Submitted to ApJ. We
encourage the reader to also review Smith et al. 2022, "Discovery of a new
Local Group Dwarf Galaxy Candidate in UNIONS: Bo\"{o}tes V" (arxiv:
2209.08242), who independently present the discovery of one of the candidates
reported here. We are working to make code and data products availabl
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