Search Publications
Two peculiar fast transients in a strongly lensed host galaxy
Sharon, K.; Diego, J. M.; Molino, A. +32 more
A massive galaxy cluster can serve as a magnifying glass for distant stellar populations, as strong gravitational lensing magnifies background galaxies and exposes details that are otherwise undetectable. In time-domain astronomy, imaging programmes with a short cadence are able to detect rapidly evolving transients, previously unseen by surveys d…
The age-velocity dispersion relation of the Galactic discs from LAMOST-Gaia data
Liu, Chao; Yu, Jincheng
We present the age-velocity dispersion relation (AVR) in three dimensions in the solar neighbourhood using 3564 commonly observed sub-giant/red giant branch stars selected from The Large Sky Area Multi-Object Fiber Spectroscopic Telescope, which gives the age and radial velocity, and Gaia, which measures the distance and proper motion. The stars a…
Variable Outer Disk Shadowing around the Dipper Star RXJ1604.3-2130
Ginski, C.; Dominik, C.; Bouvier, J. +6 more
Low brightness dips have recently been observed in images of protoplanetary disks, and they are believed to be shadows by the inner disk. We present VLT/SPHERE polarimetric differential imaging of the transition disk around the dipper star RX J1604.3-2130. We gathered 11 epochs that cover a large temporal baseline, to search for variability over t…
The Chandra COSMOS Legacy Survey: Compton thick AGN at high redshift
Vignali, C.; Gilli, R.; Comastri, A. +8 more
The existence of a large population of Compton thick (CT; NH > 1024 cm-2) active galactic nuclei (AGN) is a key ingredient of most cosmic X-ray background synthesis models. However, direct identification of these sources, especially at high redshift, is difficult due to flux suppression and complex spectral shap…
Implications of the Large O VI Columns around Low-redshift L ∗ Galaxies
Werk, Jessica K.; McQuinn, Matthew
Observations reveal massive amounts of O VI around star-forming L * galaxies, with covering fractions of near unity extending to the host halo’s virial radius. This O VI absorption is typically kinematically centered upon photoionized gas, with line widths that are suprathermal and kinematically offset from the galaxy. We discuss variou…
Extended main sequence turnoffs in open clusters as seen by Gaia - I. NGC 2818 and the role of stellar rotation
Cabrera-Ziri, I.; Usher, C.; Bastian, N. +5 more
We present an analysis of the relatively low mass (∼2400 M⊙), ∼800 Myr, Galactic open cluster, NGC 2818, using Gaia DR2 results combined with VLT/FLAMES spectroscopy. Using Gaia DR2 proper motions and parallax measurements, we are able to select a clean sample of cluster members. This cluster displays a clear extended main sequence turn…
The XXL Survey. XXV. Cosmological analysis of the C1 cluster number counts
Chiappetti, L.; Altieri, B.; Valtchanov, I. +26 more
Context. We present an estimation of cosmological parameters with clusters of galaxies.
Aims: We constrain the Ωm, σ8, and w parameters from a stand-alone sample of X-ray clusters detected in the 50 deg2 XMM-XXL survey with a well-defined selection function.
Methods: We analyse the redshift distribution o…
Planck's view on the spectrum of the Sunyaev-Zeldovich effect
Bertoldi, Frank; Chluba, Jens; Basu, Kaustuv +1 more
We present a detailed analysis of the stacked frequency spectrum of a large sample of galaxy clusters using Planck data, together with auxiliary data from the AKARI and IRAS missions. Our primary goal is to search for the imprint of relativistic corrections to the thermal Sunyaev-Zeldovich effect (tSZ) spectrum, which allow to measure the temperat…
The role of galaxies and AGN in reionizing the IGM - I. Keck spectroscopy of 5 < z < 7 galaxies in the QSO field J1148+5251
Stark, Daniel P.; Ellis, Richard S.; Bosman, Sarah E. I. +7 more
We introduce a new method for determining the influence of galaxies and active galactic nuclei (AGN) on the intergalactic medium (IGM) at high redshift and illustrate its potential via a first application to the field of the z = 6.42 QSO J1148+5251. Correlating spatial positions Lyman break galaxies (LBGs) with the Lyman alpha forest seen in the s…
Why the Shock-ICME Complex Structure Is Important: Learning from the Early 2017 September CMEs
Wang, Yuming; Shen, Chenglong; Luo, Bingxian +2 more
In the early days of 2017 September, an exceptionally energetic solar active region AR 12673 aroused great interest in the solar physics community. It produced four X class flares, more than 20 coronal mass ejections (CMEs), and an intense geomagnetic storm, for which the peak value of the Dst index reached up to -142 nT at 2017 September 8 02:00 …