Publications (53)
The UVES Large Program for Testing Fundamental Physics II: Constraints on a Change in μ Towards Quasar HE 0027-1836
H. Rahmani, M. Wendt, R. Srianand +14
We present an accurate analysis of the H2 absorption lines from the zabs ~ 2.4018 damped Lyα system towards HE 0027-1836 observed with the Very Large Telescope Ultraviolet and Vis…
The UVES Large Program for testing fundamental physics - III. Constraints on the fine-structure constant from 3 telescopes
T. M. Evans, M. T. Murphy, J. B. Whitmore +10
Large statistical samples of quasar spectra have previously indicated possible cosmological variations in the fine-structure constant, . A smaller sample of higher signal-to-no…
A High Quality/Low Computational Cost Technique for Block Matching Motion Estimation
S. Lopez, G. M. Callico, J. F. Lopez +1
Motion estimation is the most critical process in video coding systems. First of all, it has a definitive impact on the rate-distortion performance given by the video encoder. Seco…
Fundamental constants and high resolution spectroscopy
P. Bonifacio, H. Rahmani, J. B. Whitmore +14
Absorption-line systems detected in high resolution quasar spectra can be used to compare the value of dimensionless fundamental constants such as the fine-structure constant, alph…
Nitrogen-deficient and iron-rich associated absorbers with oversolar metallicities towards the quasar HE0141-3932
S. A. Levshakov, I. I. Agafonova, D. Reimers +3
HE0141-3932 (zem=1.80) is a bright blue radio-quite quasar which reveals an emission line spectrum with an unusually weak Ly-alpha line. In addition, large redshift differences (De…
The evolution of the star formation rate function in the EAGLE simulations: A comparison with UV, IR and H observations from z ~ 8 to z ~ 0
A. Katsianis, G. Blanc, C. P. Lagos +7
We investigate the evolution of the galaxy Star Formation Rate Function (SFRF) and Cosmic Star Formation Rate Density (CSFRD) of galaxies in the Evolution and Assembly…
The UVES Large Program for Testing Fundamental Physics: I Bounds on a change in alpha towards quasar HE 2217-2818
P. Molaro, M. Centurion, J. B. Whitmore +14
Absorption line systems detected in quasar spectra can be used to compare the value of the fine-structure constant, α, measured today on Earth with its value in distant galaxies.…
Galaxy Clusters in the Line of Sight to Background Quasars: II. Environmental effects on the sizes of baryonic halo sizes
N. Padilla, I. Lacerna, S. Lopez +4
Based on recent results on the frequency of MgII absorption line systems in the "QSO behind RCS clusters" survey (QbC), we analyse the effects of the cluster environment on the siz…
The Evolution of Lyman alpha Absorbers in the Redshift Range 0.5<z<1.9
E. Janknecht, D. Reimers, S. Lopez +1
We investigate the evolution and the statistical properties of the Lya absorbers of the intergalactic medium (IGM) in the largely unexplored redshift range z=0.5-1.9. We use high-r…
XQ-100: A legacy survey of one hundred 3.5 < z < 4.5 quasars observed with VLT/XSHOOTER
S. Lopez, V. D'Odorico, S. L. Ellison +23
We describe the execution and data reduction of the European Southern Observatory Large Programme "Quasars and their absorption lines: a legacy survey of the high-redshift universe…
The evolution of the Cosmic Microwave Background Temperature: Measurements of TCMB at high redshift from carbon monoxide excitation
P. Noterdaeme, P. Petitjean, R. Srianand +2
A milestone of modern cosmology was the prediction and serendipitous discovery of the Cosmic Microwave Background (CMB), the radiation left over after decoupling from matter in the…
The SEDIGISM survey: Molecular clouds in the inner Galaxy
A. Duarte-Cabral, D. Colombo, J. S. Urquhart +57
We use the 13CO(2-1) emission from the SEDIGISM high-resolution spectral-line survey of the inner Galaxy, to extract the molecular cloud population with a large dynamic range in sp…
Chemical abundances of damped Lyman alpha systems in the XQ-100 survey
T. A. M. Berg, S. L. Ellison, R. Sanchez-Ramirez +8
The XQ-100 survey has provided high signal-noise spectra of 100 redshift 3-4.5 quasars with the X-Shooter spectrograph. The metal abundances for 13 elements in the 41 damped Lyman…
Solving the conundrum of intervening strong MgII absorbers towards GRBs and quasars
L. Christensen, S. D. Vergani, S. Schulze +33
Previous studies have shown that the incidence rate of intervening strong MgII absorbers towards GRBs were a factor of 2 - 4 higher than towards quasars. Exploring the similar size…
Orientation effects on cool gas absorption from gravitational-arc tomography of a z = 0.77 disc galaxy
A. Fernandez-Figueroa, S. Lopez, N. Tejos +11
We use spatially-resolved spectroscopy of a distant giant gravitational arc to test orientation effects on MgII absorption equivalent width (EW) and covering fraction (kappa) in th…
Diffuse molecular gas at high redshift: Detection of CO molecules and the 2175 Ã dust feature at z=1.64
P. Noterdaeme, C. Ledoux, R. Srianand +2
We present the detection of carbon monoxide molecules (CO) at z=1.6408 towards the quasar SDSSJ160457.50+220300.5 using the VLT Ultraviolet and Visual Echelle Spectrograph. CO abso…
JWST Observations of Starbursts: Relations between PAH features and CO clouds in the starburst galaxy M 82
V. Villanueva, A. D. Bolatto, R. Herrera-Camus +22
We present a study of new 7.7-11.3 m data obtained with the James Webb Space Telescope Mid-InfraRed Instrument in the starburst galaxy M 82. In particular, we focus on the depe…
Implementation of the Principal Component Analysis onto High-Performance Computer Facilities for Hyperspectral Dimensionality Reduction: Results and Comparisons
E. Martel, R. Lazcano, J. Lopez +7
Dimensionality reduction represents a critical preprocessing step in order to increase the efficiency and the performance of many hyperspectral imaging algorithms. However, dimensi…
Hunting for Metals Using XQ-100 Legacy Survey Composite Spectra
S. Perrotta, V. D'Odorico, F. Hamann +10
We investigate the NV absorption signal along the line of sight of background quasars, in order to test the robustness of the use of this ion as criterion to select intrinsic (i.e.…
Galaxy Clusters in the Line of Sight to Background Quasars: I. Survey Design and Incidence of MgII Absorbers at Cluster Redshifts
S. Lopez, L. F. Barrientos, P. Lira +7
We describe the first optical survey of absorption systems associated with galaxy clusters at z= 0.3-0.9. We have cross-correlated SDSS DR3 quasars with high-redshift cluster/group…
HE 0141-3932: a bright QSO with an unusual emission line spectrum and associated absorption
D. Reimers, E. Janknecht, C. Fechner +3
HE 0141-3932 (zem = 1.80) is a bright blue radio-quite quasar with an unusually weak Ly-alpha emission line. Large redshift differences (Delta z = 0.05) are observed between high i…
A new measure of Delta alpha/alpha at redshift z = 1.84 from very high resolution spectra of Q1101-264
S. A. Levshakov, P. Molaro, S. Lopez +5
We probe the evolution of the fine-structure constant, alpha, with cosmic time. Accurate positions of the FeII lines 1608, 2382,and 2600 A are measured in the z = 1.84 absorption s…
On the Incidence of Strong MgII Absorbers Along GRB Sightlines
G. E. Prochter, J. X. Prochaska, H. -W. Chen +7
We report on a survey for strong (rest equivalent width W_r >= 1A), intervening MgII systems along the sightlines to long-duration gamma-ray bursts (GRBs). The GRB spectra which co…
Clues to the origin of metals in the Ly-alpha forest
S. Lopez, S. D'odorico, S. L. Ellison +1
We analyze the z=2 Ly-alpha and CIV forest along two adjacent lines-of-sight at high S/N and spectral resolution to assess the question of the origin of metals in the intergalactic…
Metallicities, dust and molecular content of a QSO-Damped Lyman-α system reaching log N (H i) = 22: An analog to GRB-DLAs
R. Guimarães, P. Noterdaeme, P. Petitjean +4
We present the elemental abundance and H2 content measurements of a Damped Lyman-α (DLA) system with an extremely large H i column density, log N(H i) (cm-2) = 22.0+/-0.10, at zab…
Afterglow Observations of Fermi-LAT Gamma-Ray Bursts and the Emerging Class of Hyper-Energetic Events
S. B. Cenko, D. A. Frail, F. A. Harrison +21
We present broadband (radio, optical, and X-ray) light curves and spectra of the afterglows of four long-duration gamma-ray bursts (GRBs 090323, 090328, 090902B, and 090926A) detec…
GRB 080503: Implications of a Naked Short Gamma-Ray Burst Dominated by Extended Emission
D. A. Perley, B. D. Metzger, J. Granot +22
We report on observations of GRB 080503, a short gamma-ray burst with very bright extended emission (about 30 times the gamma-ray fluence of the initial spike) in conjunction with…
Directly constraining the spatial coherence of the circumgalactic medium
A. Afruni, S. Lopez, P. Anshul +9
One of the biggest puzzles regarding the circumgalactic medium (CGM) is the structure of its cool ( K) gas phase. While the kinematics of quasar absorption systems sugge…
The Host Galaxies of Swift Dark Gamma-Ray Bursts: Observational Constraints on Highly Obscured and Very High-Redshift GRBs
D. A. Perley, S. B. Cenko, J. S. Bloom +13
In this work we present the first results of our imaging campaign at Keck Observatory to identify the host galaxies of "dark" gamma-ray bursts (GRBs), events with no detected optic…
Spatially Resolved Outflows in a Seyfert Galaxy at z = 2.39
Travis C. Fischer, J. R. Rigby, G. Mahler +11
We present the first spatially resolved analysis of rest-frame optical and UV imaging and spectroscopy for a lensed galaxy at z = 2.39 hosting a Seyfert active galactic nucleus (AG…
The multiple coherence scales of C IV at cosmic noon
H. Cortés-Muñoz, S. Lopez, N. Tejos +6
The spatial and kinematic structure of the circumgalactic medium (CGM) remains poorly constrained observationally. In this article we compute the clustering of CIV absorption syste…
The effects of viewing angle on the mass distribution of exoplanets
S. Lopez, J. S. Jenkins
We present a mathematical method to statistically decouple the effects of unknown inclination angles on the mass distribution of exoplanets that have been discovered using radial-v…
Dark energy with gravitational lens time delays
T. Treu, P. J. Marshall, F. -Y. Cyr-Racine +35
Strong lensing gravitational time delays are a powerful and cost effective probe of dark energy. Recent studies have shown that a single lens can provide a distance measurement wit…
Galaxy Clusters in the Line of Sight to Background Quasars - III Multi-Object Spectroscopy
H. Andrews, L. F. Barrientos, S. Lopez +8
We present Gemini/GMOS-S multi-object spectroscopy of 31 galaxy cluster candidates at redshifts between 0.2 and 1.0 and centered on QSO sight-lines taken from Lopez et al. (2008).…
Disentangling microlensing and differential extinction in the double QSO HE0512-3329
O. Wucknitz, L. Wisotzki, S. Lopez +1
We present the first separate spectra of both components of the small-separation double QSO HE0512-3329 obtained with HST/STIS in the optical and near UV. The similarities especial…
An Independent Measurement of the Incidence of MgII Absorbers along Gamma-Ray Burst Sightlines: the End of the Mystery?
A. Cucchiara, J. X. Prochaska, G. Zhu +15
In 2006, Prochter et al. reported a statistically significant enhancement of very strong Mg II absorption systems intervening the sightlines to gamma-ray bursts (GRBs) relative to…
High-Redshift Starbursting Dwarf Galaxies Revealed by GRB Afterglows
Hsiao-Wen Chen, Daniel A. Perley, Lindsey K. Pollack +7
We present a study of 15 long-duration gamma-ray burst (GRB) host galaxies at z>2. The GRBs are selected with available early-time afterglow spectra in order to compare interstella…
The Multiwavelength Survey by Yale-Chile (MUSYC): Survey Design and Deep Public UBVRIz' Images and Catalogs of the Extended Hubble Deep Field South
MUSYC Collaboration, E. Gawiser, P. G. van Dokkum +25
We present UBVRIz' optical images of the 0.32 square degree Extended Hubble Deep Field South. This is one of four fields comprising the MUSYC survey, which is optimized for the stu…
Cosmochemistry, Cosmology and Fundamental Constants: High-Resolution Spectroscopy of Damped Lyman-Alpha Systems
R. Quast, D. Reimers, A. Smette +4
Spectroscopy of QSO absorption lines provides essential observational input for the study of nucleosynthesis and chemical evolution of galaxies at high redshift. But new observatio…
Transverse clues on the kpc-scale structure of the circumgalactic medium as traced by C IV absorption
S. Lopez, A. Afruni, D. Zamora +13
We present VLT/MUSE integral-field spectroscopy () of four giant gravitational arcs exhibiting strong C IV absorption at 8 intervening redshifts, $z_{abs}\approx 2…
On the selection of damped Lyman alpha systems using MgII absorption at 2<z<4
T. A. M. Berg, S. L. Ellison, J. X. Prochaska +8
The XQ-100 survey provides optical and near infrared coverage of 36 blindly selected, intervening damped Lyman alpha systems (DLAs) at 2 < z < 4, simultaneously covering the MgII d…
Tomography of the intergalactic medium with Ly-alpha forests in close QSO pairs
V. D'Odorico, M. Viel, F. Saitta +6
We study the three-dimensional distribution of non virialised matter at z~2 using high resolution spectra of QSO pairs and simulated spectra drawn from cosmological hydrodynamical…
Observations of the Naked-Eye GRB 080319B: Implications of Nature's Brightest Explosion
J. S. Bloom, D. A. Perley, W. Li +18
The first gamma-ray burst (GRB) confirmed to be bright enough to be seen with the naked eye, GRB 080319B at redshift z = 0.937, allowed for exquisite follow-up observations across…
Clues to the nature of high-redshift OVI absorption systems from their (lack of) small-scale structure
S. Lopez, S. Ellison, S. D'Odorico +1
We present results of the first survey of high-redshift (<z> ~ 2.3) OVI absorption systems along parallel lines of sight toward two lensed QSOs. After a careful and well-defined se…
The SEDIGISM survey: first data release and overview of the Galactic structure
F. Schuller, J. S. Urquhart, T. Csengeri +57
The SEDIGISM (Structure, Excitation and Dynamics of the Inner Galactic Interstellar Medium) survey used the APEX telescope to map 84 deg^2 of the Galactic plane between l = -60 deg…
The evolution of the Si IV content in the Universe from the epoch of reionization to cosmic noon
V. D'Odorico, K. Finlator, S. Cristiani +9
We investigate the abundance and distribution of metals in the high-redshift intergalactic medium and circum-galactic medium through the analysis of a sample of almost 600 SiIV abs…
Evidence for a magnitude-dependent bias in the Hamburg/ESO Survey for Damped Lyman-alpha Systems
A. Smette, L. Wisotzki, C. Ledoux +3
We present preliminary results from the Hamburg/ESO survey for Damped Ly-alpha (hereafter, DLA) Systems. This survey is characterized by (i) the good knowledge of the biases affect…
Evidence of First Stars-enriched Gas in High-redshift Absorbers
A. Saccardi, S. Salvadori, V. D'Odorico +6
The first stars were born from chemically pristine gas. They were likely massive, and thus they rapidly exploded as supernovae, enriching the surrounding gas with the first heavy e…
Slicing the cool circumgalactic medium along the major-axis of a star-forming galaxy at
S. Lopez, N. Tejos, L. F. Barrientos +13
We present spatially-resolved echelle spectroscopy of an intervening MgII-FeII-MgI absorption-line system detected at toward the giant gravitational arc PSZ1…
Spectral shape of the UV ionizing background and OVI absorbers at z ~ 1.5 towards HS0747+4259
D. Reimers, I. I. Agafonova, S. A. Levshakov +5
We report on high resolution spectra of the bright QSO HS0747+4259 (zem = 1.90, V = 15.8) observed to search for intermediate redshift OVI absorption systems. The spectra were obta…
Probing 3-D matter distribution at z~2 with QSO multiple lines of sight
S. Cristiani, V. D'Odorico, F. Saitta +6
We investigate the 3-D matter distribution at z~2 with high resolution (R ~ 40000) spectra of QSO pairs and groups obtained with the UVES spectrograph at ESO VLT. Our sample is uni…
Metal Abundances in a Damped Lyman-alpha System Along Two Lines of Sight at z=0.93
S. Lopez, D. Reimers, M. D. Gregg +3
We study metal abundances in the z=0.9313 damped Lya system observed in the two lines-of-sight, A and B, toward the gravitationally-lensed double QSO HE0512-3329. Spatially resolve…
A translucent interstellar cloud at z=2.69: CO, H2 and HD in the line-of-sight to SDSS J123714.60+064759.5
P. Noterdaeme, P. Petitjean, C. Ledoux +3
We present the analysis of a sub-DLA system (log N(H^0)=20.0+/-0.15, z_abs=2.69) toward SDSS J123714+064759 (z_em=2.78). Using the VLT/UVES and X-shooter spectrographs, we detect H…