A5071059947- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Scientific Research and Discoveries
- Cosmology and Gravitation Theories
- Radio Astronomy Observations and Technology
- Astronomical Observations and Instrumentation
- CCD and CMOS Imaging Sensors
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Adaptive optics and wavefront sensing
- Calibration and Measurement Techniques
- Thin-Film Transistor Technologies
- Geophysics and Gravity Measurements
- Spectroscopy and Laser Applications
- Impact of Light on Environment and Health
- Phase Equilibria and Thermodynamics
- Mechanics and Biomechanics Studies
- Astro and Planetary Science
- History and Developments in Astronomy
- Analytical Chemistry and Sensors
- GaN-based semiconductor devices and materials
- Black Holes and Theoretical Physics
Space Telescope Science Institute
2020-2024
Laboratoire d’Astrophysique de Marseille
2015-2024
Aix-Marseille Université
2015-2024
Centre National de la Recherche Scientifique
2015-2024
The Ohio State University
2019-2024
University College London
2023
University of South Carolina
2010-2017
S.N. Bose National Centre for Basic Sciences
2008
WEAVE, the new wide-field, massively multiplexed spectroscopic survey facility for William Herschel Telescope, will see first light in late 2022. WEAVE comprises a 2-degree field-of-view prime-focus corrector system, nearly 1000-multiplex fibre positioner, 20 individually deployable 'mini' integral field units (IFUs), and single large IFU. These systems feed dual-beam spectrograph covering wavelength range 366$-$959\,nm at $R\sim5000$, or two shorter ranges $R\sim20\,000$. After summarising...
We report observations of four sub-damped Lyman-alpha (sub-DLA) quasar absorbers at z<0.5 obtained with the Hubble Space Telescope Cosmic Origins Spectrograph. measure available neutrals or ions C, N, O, Si, P, S, Ar, Mn, Fe, and/or Ni. Our data have doubled sub-DLA metallicity samples and improved constraints on chemical evolution. All our sub-DLAs are consistent near-solar super-solar metallicities relatively modest ionization corrections; more lines detailed modeling will help to verify...
We report the discovery of a "super-damped" Lyα absorber at zabs = 2.2068 toward quasi-stellar object (QSO) Q1135-0010 in Sloan Digital Sky Survey (SDSS) and follow-up Very Large Telescope (VLT) UVES spectroscopy. A Voigt profile fit to damped (DLA) line indicates log . This is second QSO DLA discovered date with such high derive element abundances [Si/H] −1.10 ± 0.10, [Zn/H] −1.06 [Cr/H] −1.55 [Ni/H] −1.60 [Fe/H] −1.76 [Ti/H] −1.69 0.11, [P/H] −0.93 0.23, [Cu/H] −0.75 0.14. Our data...
We present a new photometric calibration of the WFC3-UVIS and WFC3-IR detectors based on observations collected from 2009 to 2020 for four white dwarfs, namely GRW+70~5824, GD~153, GD~71, G191B2B, G-type star, P330E. These calibrations include recent updates Hubble Space Telescope primary standard dwarf models reference flux Vega. Time-dependent inverse sensitivities two chips, UVIS1 UVIS2, were calculated all 42 full-frame filters, after accounting temporal changes in observed count rates...
Abstract We present the first Data Release (DR1) from Hubble Space Telescope (HST) Ultraviolet Legacy Library of Young Stars as Essential Standards (ULLYSES) program, a Director’s Discretionary program devoting approximately 1000 HST orbits to production an ultraviolet spectroscopic library young high- and low-mass stars in local universe. The science products this release are combined individual, extracted calibrated spectra obtained with COS STIS instruments aboard HST. Products made using...
We present chemical abundance measurements from high-resolution observations of five sub-damped Lyman α absorbers (sub-DLAs) at 1.7 < z 2.4 observed with the Magellan Inamori Kyocera Echelle (MIKE) spectrograph on 6.5-m II (Clay) telescope. Lines Zn ii, Mg i, Al iii, S Si iv, C ii*, Ni Mn ii and Fe were detected column densities determined. The metallicity absorbing gas, inferred nearly undepleted element Zn, is in range <−0.95 to +0.25 dex for our sample, three systems being near-solar or...
Damped Lyman-alpha (DLA) and sub-DLA absorbers in quasar spectra provide the most sensitive tools for measuring element abundances of distant galaxies. Estimation from absorption lines depends sensitively on accuracy atomic data used. We have started a project to produce new spectroscopic parameters optical/UV spectral using state-of-the-art computer codes employing very broad configuration interaction basis. Here we report our results Zn II, an ion used widely studies interstellar medium...
ABSTRACT We study of the properties a new class circumgalactic medium absorbers identified in Ly α forest: ‘Strong, Blended Lyman-α’ (or SBLA) absorption systems. SBLAs at 2.4 &lt; z 3.1 SDSS-IV/eBOSS spectra by their strong extended complexes covering 138 $\, \, {\rm km}\, s}^{-1}$ with an integrated $\log (N_{\rm H\, {\small I}}/\mathrm{cm}^{-2}) =16.04$$\substack{+0.05 \\ -0.06}$ and Doppler parameter b = 18.1$\substack{+0.7 -0.4}$$\, s}^{-1}$. Clustering forest provides large-scale...
We present the first clustering measurement of Strong Blended Lyman $\alpha$ (SBLA) absorption systems by measuring their cross-correlation with forest. SBLAs are a new population absorbers detected within find bias $2.329\pm0.057$, consistent that Damped (DLAs). For DLAs, we recover $2.331\pm0.057$ larger than previously reported (P\'erez-R\`afols et al. 2018b). also redshift space distortion parameter $\beta=0.417\pm0.010$, recovered value for DLAs ($\beta=0.416\pm0.010$). This is SBLA and...
We report Keck/Echellette Spectrograph and Imager Very Large Telescope/Ultraviolet-Visual Echelle observations of three super-damped Lyα quasar absorbers with H i column densities log NH ≥ 21.7 at redshifts 2 ≲ z 2.5. All show similar metallicities (∼−1.3 to −1.5 dex), dust depletion Fe, Ni, Mn. Two the supersolar [S/Zn] [Si/Zn]. combine our results those for other damped a (DLAs) examine trends between i, metallicity, depletion. A larger fraction super-DLAs lie close or above line [X/H] =...
WEAVE, the new wide-field, massively multiplexed spectroscopic survey facility for William Herschel Telescope, will see first light in late 2022. WEAVE comprises a 2-degree field-of-view prime-focus corrector system, nearly 1000-multiplex fibre positioner, 20 individually deployable 'mini' integral field units (IFUs), and single large IFU. These systems feed dual-beam spectrograph covering wavelength range 366$-$959\,nm at $R\sim5000$, or two shorter ranges $R\sim20\,000$. After summarising...
We report on a study of interstellar silicate dust in five quasar absorption systems at 0.44 < zabs 1.31 toward quasars Q0235+164, 3C196, Q0852+3435, Q0937+5628, and Q1203+0634, using data from the Infrared Spectrograph board Spitzer Space Telescope. In absorbers 9.7 μm feature is detected ∼5σ–10σ significance, with rest-frame equivalent widths ∼0.2–0.5 μm. For noisy allow us to make only 3.6σ detection 10 Fits redshifted features four possible template profiles indicate that laboratory...
We present evidence of a >10-sigma detection the 10 micron silicate dust absorption feature in spectrum gravitationally lensed quasar PKS 1830-211, produced by foreground system at redshift 0.886. have examined more than 100 optical depth templates, derived from both observations Galactic and extragalactic sources laboratory measurements, order to constrain chemical structure dust. find that best fit observed profile is crystalline olivine, with corresponding peak tau_10=0.27+/-0.05. The...
We present abundance measurements of elements O, C, Si and Fe for three gas-rich galaxies at z~5 using observations from the Very Large Telescope (VLT) Keck telescope in order to better constrain early chemical enrichment galaxies. These show strong Lyman-{\alpha} absorption spectra background quasars, with neutral hydrogen column densities log N${_H{}_I}$(cm$^{-2}$)=20.10$\pm$0.15, 20.10$\pm$0.15, 20.80$\pm$0.15. Using undepleted element we find metallicities [O/H] be range -2.51 -2.05 dex....
Absorption spectroscopy of gravitationally lensed quasars (GLQs) enables study spatial variations in the interstellar and/or circumgalactic medium foreground galaxies. We report observations 4 GLQs, each with two images separated by 0.8-3.0", that show strong absorbers at redshifts 0.4$<$$z_{abs}$$<$1.3 their spectra, including some lens redshift impact parameters 1.5-6.9 kpc. measure H I Lyman lines along sight five (10 total) using HST STIS, and metal Magellan Echellette or Sloan Digital...
Abstract We report on the discovery of a UV absorption counterpart low-ionization X-ray ultrafast outflow (UFO) in narrow-line Seyfert 1 galaxy IRAS 17020+4544. This signature UFO is seen as narrow and blueshifted Ly α feature far-UV spectrum, taken with Cosmic Origins Spectrograph (COS) Hubble Space Telescope (HST). The found to be outflowing velocity −23,430 km s −1 (0.078 c ). carry out high-resolution spectroscopy photoionization modeling study that HTS/COS spectrum. results our show...
We present SQUEzE, a software package to classify quasar spectra and estimate their redshifts. SQUEzE is random forest classifier operating on the parameters of candidate emission peaks identified in spectra. test performance algorithm using visually inspected data from BOSS as truth table. Only 4\% sample ($\sim$6,800 quasars $\sim$11,520 contaminants) needed for converged training recommended choices confidence threshold ($0.2<p_{\rm min}<0.7$). For an operational mode which balances...
Element abundances in high-redshift quasar absorbers offer excellent probes of the chemical enrichment distant galaxies, and can constrain models for population III early II stars. Recent observations indicate that sub-damped Lyman-alpha (sub-DLA) are more metal-rich than DLA at redshifts 0$<$$z$$<$3. It has also been suggested metallicity drops suddenly $z$$>$4.7. However, only 3 DLAs $z$$>$4.5 none $z$$>$3.5 have "dust-free" measurements undepleted elements. We report first sub-DLA...
Abstract The Hubble Space Telescope (HST) Ultraviolet Legacy Library of Young Stars as Essential Standards (ULLYSES) program is a HST Director's Discretionary that in the process obtaining large library ultraviolet spectroscopic observations young stars both high and low masses. We present information on close companions to T Tauri CVSO 109 165 Orion were observed with part this program. has fainter companion at an angular separation ρ = 0.″64 near PA 218° Δ(F28X50LP) ≈ 0.6 mag, while 0.″30...
We present the first clustering measurement of Strong Blended Lyman $α$ (SBLA) absorption systems by measuring their cross-correlation with forest. SBLAs are a new population absorbers detected within find bias $2.329\pm0.057$, consistent that Damped (DLAs). For DLAs, we recover $2.331\pm0.057$ larger than previously reported (Pérez-Ràfols et al. 2018b). also redshift space distortion parameter $β=0.417\pm0.010$, recovered value for DLAs ($β=0.416\pm0.010$). This is SBLA and DLA tracing...
We study large-scale UV background inhomogeneity in three-dimensions associated with the observed quasar populations at high redshift. do this by measuring metal absorption through spectrum stacking as a function distance to closest SDSS-IV/eBOSS on 10s of comoving megaparsec scales. both intergalactic medium absorbers and mixed circumgalactic probe O VI, C IV, Si III. Overall stronger ionization species is seen closer quasars $2.4<z<3.1$. VI shows particularly strong change, effects IV...
Quasi-Periodic Oscillations (QPOs) are very puzzling since they remain totally unexplained by popular earlier models of accretion disks. The significant rms value in power density spectrum implies that the oscillation involves dynamical and non-linear variation certain region disk itself. nature energy dependence which produces Comptonized hard tail is also responsible for QPOs. Similarly, occurrences QPOs strongly related to jet formation spectral states. These features natural consequences...
High signal-to-noise spectra toward background quasars are crucial for uncovering weak absorption in the circumgalactic medium (CGM) of intervening galaxies, such as diagnostic lines N V that provide insight to ionization process warm gas but typically have low equivalent widths. We present a new spectrum from Hubble Space Telescope with ratio $\sim20-35$ quasar SDSS J1009+0713 and analyze systems CGM two $L^\star$ galaxies close line sight. identify additional these was not reported by...