Search Publications
Gaia reference frame amid quasar variability and proper motion patterns in the data
Lindegren, L.; Hobbs, D.; Bachchan, R. K.
Context. Gaia's very accurate astrometric measurements will allow the optical realisation of the International Celestial Reference System to be improved by a few orders of magnitude. Several sets of quasars are used to define a kinematically stable non-rotating reference frame with the barycentre of the solar system as its origin. Gaia will also o…
Interrupted Eruption of Large Quiescent Filament Associated with a Halo CME
Filippov, Boris; Chandra, Ramesh; Gosain, S. +1 more
We analyze the observations of an eruptive quiescent filament associated with a halo Coronal Mass Ejection (CME). We use observations from the Atmospheric Imaging Assembly (AIA) instrument onboard the Solar Dynamics Observatory (SDO), Solar and Heliospheric Observatory (SOHO)/Large Angle and Spectrometric Coronagraph (LASCO), and the Solar Terrest…
The Stellar Mass Fundamental Plane and Compact Quiescent Galaxies at z < 0.6
Hwang, Ho Seong; Geller, Margaret J.; Damjanov, Ivana +2 more
We examine the evolution of the relation between stellar mass surface density, velocity dispersion, and half-light radius—the stellar mass fundamental plane (MFP)—for quiescent galaxies at z < 0.6. We measure the local relation from galaxies in the Sloan Digital Sky Survey and the intermediate redshift relation from ∼500 quiescent galaxies with…
The structure and evolution of a forming galaxy cluster at z = 1.62
Hartley, W. G.; Conselice, C. J.; Almaini, O. +4 more
We present a comprehensive picture of the Cl 0218.3-0510 protocluster at z = 1.623 across 10 comoving Mpc. Using filters that tightly bracket the Balmer and 4000 Å breaks of the protocluster galaxies we obtain precise photometric redshifts resulting in a protocluster galaxy sample that is 89 ± 5 per cent complete and has a contamination of only 12…
The radial speed-expansion speed relation for Earth-directed CMEs
Gopalswamy, N.; Yashiro, S.; Mäkelä, P.
Earth-directed coronal mass ejections (CMEs) are the main drivers of major geomagnetic storms. Therefore, a good estimate of the disturbance arrival time at Earth is required for space weather predictions. The STEREO and SOHO spacecraft were viewing the Sun in near quadrature during January 2010 to September 2012, providing a unique opportunity to…
The XXL Survey. XII. Optical spectroscopy of X-ray-selected clusters and the frequency of AGN in superclusters
Altieri, B.; Valtchanov, I.; Pierre, M. +13 more
Context. This article belongs to the first series of XXL publications. It presents multifibre spectroscopic observations of three 0.55 deg2 fields in the XXL Survey, which were selected on the basis of their high density of X-ray-detected clusters. The observations were obtained with the AutoFib2+WYFFOS (AF2) wide-field fibre spectrogra…
Unveiling the Physics of Low-luminosity AGNs through X-Ray Variability: LINER versus Seyfert 2
González-Martín, O.; Perea, J.; Márquez, I. +2 more
X-ray variability is very common in active galactic nuclei (AGNs), but these variations may not occur similarly in different families of AGNs. We aim to disentangle the structure of low-ionization nuclear emission-line regions (LINERs) compared to Seyfert 2s by the study of their spectral properties and X-ray variations. We assembled the X-ray spe…
Linking low- to high-mass young stellar objects with Herschel-HIFI observations of water
Braine, J.; van Dishoeck, E. F.; Johnstone, D. +7 more
Context. Water probes the dynamics in young stellar objects (YSOs) effectively, especially shocks in molecular outflows. It is therefore a key molecule for exploring whether the physical properties of low-mass protostars can be extrapolated to massive YSOs, an important step in understanding the fundamental mechanisms regulating star formation.
The PEP survey: evidence for intense star-forming activity in the majority of radio-selected AGN at z ≳ 1
Berta, S.; Lutz, D.; Popesso, P. +4 more
In order to investigate the far-infrared (FIR) properties of radio-active active galactic nuclei (AGN), we have considered three different fields where both radio and FIR observations are the deepest to date: GOODS-South, GOODS-North and the Lockman Hole. Out of a total of 92 radio-selected AGN, ∼64 per cent are found to have a counterpart in Hers…
PALOMA: A Magnetic CV between Polars and Intermediate Polars
Pandey, J. C.; Singh, K. P.; Joshi, Arti +1 more
We present analyses of archival X-ray data obtained from the XMM-Newton satellite and optical photometric data obtained from 1 m class telescopes of ARIES, Nainital of a magnetic cataclysmic variable (MCV) Paloma. Two persistent periods at 156 ± 1 minutes and 130 ± 1 minutes are present in the X-ray data, which we interpret as the orbital and spin…