Search Publications
A study of the circumgalactic medium at z ∼ 0.6 using damped Lyman α galaxies
Turnshek, David A.; Rao, Sandhya M.; Kulkarni, Varsha P. +6 more
We present the study of a sample of nine quasi-stellar object fields, with damped Lyman α (DLA) or sub-DLA systems at z ∼ 0.6, observed with the X-Shooter spectrograph at the Very Large Telescope. By suitably positioning the X-Shooter slit based on high spatial resolution images of Hubble Space Telescope/Advanced Camera for Surveys we are able to …
Acceleration of the universe: a reconstruction of the effective equation of state
Mukherjee, Ankan
This work is based upon a parametric reconstruction of the effective or total equation of state in a model for the Universe with accelerated expansion. The constraints on the model parameters are obtained by maximum-likelihood analysis using the supernova distance modulus data, observational Hubble data, baryon acoustic oscillation data and cosmic…
Sizes, colour gradients and resolved stellar mass distributions for the massive cluster galaxies in XMMUJ2235-2557 at z = 1.39
Bender, Ralf; Mendel, J. Trevor; Cappellari, Michele +13 more
We analyse the sizes, colour gradients and resolved stellar mass distributions for 36 massive and passive galaxies in the cluster XMMUJ2235-2557 at z = 1.39 using optical and near-infrared Hubble Space Telescope (HST) imaging. We derive light-weighted Sérsic fits in five HST bands (I775, z850, Y105, J125…
The outburst decay of the low magnetic field magnetar SWIFT J1822.3-1606: phase-resolved analysis and evidence for a variable cyclotron feature
Mereghetti, Sandro; Esposito, Paolo; Turolla, Roberto +12 more
We study the timing and spectral properties of the low-magnetic field, transient magnetar SWIFT J1822.3-1606 as it approached quiescence. We coherently phase-connect the observations over a time-span of ∼500 d since the discovery of SWIFT J1822.3-1606 following the Swift-Burst Alert Telescope (BAT) trigger on 2011 July 14, and carried out a detail…
Extinction law in the range 0.4-4.8 µm and the 8620 Å DIB towards the stellar cluster Westerlund 1
Rubinho, M. S.; Almeida, L. A.; Damineli, A. +4 more
The young stellar cluster Westerlund 1 (Wd 1: l = 339.6°, b = -0.4°) is one of the most massive in the local Universe, but accurate parameters are pending on better determination of its extinction and distance. Based on our photometry and data collected from other sources, we have derived a reddening law for the cluster line-of-sight representativ…
Giant Metrewave Radio Telescope observations of neutral atomic hydrogen gas in the COSMOS field at z ∼ 0.37
Chengalur, Jayaram N.; Colless, Matthew; Rhee, Jonghwan +2 more
We present the results of H I spectral stacking analysis of Giant Metrewave Radio Telescope (GMRT) observations targeting the Cosmological Evolution Survey (COSMOS) field. The GMRT data cube contains 474 field galaxies with redshifts known from the zCOSMOS-bright 10 k catalogue. Spectra for the galaxies are co-added and the stacked spectrum allows…
Spatially resolved integral field spectroscopy of the ionized gas in IZw18
Kunth, D.; Durret, F.; Brinchmann, J. +6 more
We present a detailed 2D study of the ionized ionized interstellar medium (ISM) of IZw18 using new Potsdam Multi-Aperture Spectrophotometer-integral field unit (PMAS-IFU) optical observations. IZw18 is a high-ionization galaxy which is among the most metal-poor starbursts in the local Universe. This makes IZw18 a local benchmark for understanding …
The selective effect of environment on the atomic and molecular gas-to-dust ratio of nearby galaxies in the Herschel Reference Survey
Ciesla, L.; Boquien, M.; Baes, M. +10 more
We combine dust, atomic (H I) and molecular (H2) hydrogen mass measurements for 176 galaxies in the Herschel Reference Survey to investigate the effect of environment on the gas-to-dust mass (Mgas/Mdust) ratio of nearby galaxies. We find that, at fixed stellar mass, the average Mgas/Mdust rati…
The near-to-mid infrared spectrum of quasars
Alonso-Herrero, Almudena; Hatziminaoglou, Evanthia; Hernán-Caballero, Antonio +1 more
We analyse a sample of 85 luminous (log (νLν(3 µm)/erg s-1) > 45.5) quasars with rest frame ∼2-11 µm spectroscopy from AKARI and Spitzer. Their high luminosity allows a direct determination of the near-infrared quasar spectrum free from host galaxy emission. A semi-empirical model consisting of a single templat…
An enhanced merger fraction within the galaxy population of the SSA22 protocluster at z = 3.1
Lehmer, B. D.; Alexander, D. M.; Matsuda, Y. +3 more
The overdense environments of protoclusters of galaxies in the early Universe (z > 2) are expected to accelerate the evolution of galaxies, with an increased rate of stellar mass assembly and black hole accretion compared to co-eval galaxies in the average density `field'. These galaxies are destined to form the passive population of massive ga…