Search Publications
Effects of the variability of the nucleus of NGC 1275 on X-ray observations of the surrounding intracluster medium
Fabian, A. C.; Pinto, C.; Russell, H. R. +2 more
The active galaxy NGC 1275 lies at the centre of the Perseus cluster of galaxies, which is the X-ray brightest cluster in the Sky. The nucleus shows large variability over the past few decades. We compile a light curve of its X-ray emission covering about 40 years and show that the bright phase around 1980 explains why the inner X-ray bubbles were…
The morphology of the sub-giant branch and red clump reveal no sign of age spreads in intermediate-age clusters
Bastian, N.; Niederhofer, F.
A recent surprise in stellar cluster research, made possible through the precision of Hubble Space Telescope photometry, was that some intermediate-age (1-2 Gyr) clusters in the Large and Small Magellanic Clouds have main-sequence turn-off (MSTO) widths that are significantly broader than would be expected for a simple stellar population (SSP). On…
Probing gravity at large scales through CMB lensing
Ho, Shirley; Alam, Shadab; Pullen, Anthony R.
We describe a methodology to probe gravity with the cosmic microwave background (CMB) lensing convergence κ, specifically by measuring EG, the ratio of the Laplacian of the gravitational scalar potential difference to the velocity divergence. Using CMB lensing instead of galaxy-galaxy lensing avoids intrinsic alignments while also lacki…
First measurement of H I 21 cm emission from a GRB host galaxy indicates a post-merger system
Kanekar, Nissim; Michałowski, Michał J.; Roychowdhury, Sambit +2 more
We report the detection and mapping of atomic hydrogen in H I 21 cm emission from ESO 184-G82, the host galaxy of the gamma-ray burst 980425. This is the first instance where H I in emission has been detected from a galaxy hosting a gamma-ray burst (GRB). ESO 184-G82 is an isolated galaxy and contains a Wolf-Rayet region close to the location of t…
Dust-to-gas ratio, XCO factor and CO-dark gas in the Galactic anticentre: an observational study
Huang, Y.; Chen, B. -Q.; Xiang, M. -S. +2 more
We investigate the correlation between extinction and H I and CO emission at intermediate and high Galactic latitudes (|b| > 10°) within the footprint of the Xuyi Schmidt Telescope Photometric Survey of the Galactic anticentre (XSTPS-GAC) on small and large scales. In Paper I, we present a three-dimensional (3D) dust extinction map within the f…
The analysis of realistic stellar Gaia mock catalogues - I. Red clump stars as tracers of the central bar
Figueras, F.; Antoja, T.; Romero-Gómez, M. +2 more
In this first paper, we simulate the population of disc red clump stars to be observed by Gaia. We generate a set of test particles and we evolve it in a 3D barred Milky Way like galactic potential. We assign physical properties of the red clump trace population and a realistic 3D interstellar extinction model. We add Gaia observational constraint…
GTC OSIRIS transiting exoplanet atmospheric survey: detection of potassium in HAT-P-1b from narrow-band spectrophotometry
Pont, F.; Fortney, J. J.; Lecavelier des Etangs, A. +7 more
We present the detection of potassium in the atmosphere of HAT-P-1b using optical transit narrow-band photometry. The results are obtained using the 10.4-m Gran Telescopio Canarias together with the OSIRIS instrument in tunable filter imaging mode. We observed four transits, two at continuum wavelengths outside the potassium feature, at 6792 and 8…
The Seyfert 2 galaxy NGC 2110: hard X-ray emission observed by NuSTAR and variability of the iron Kα line
Harrison, F.; Stern, D.; Bauer, F. E. +16 more
We present NuSTAR observations of the bright Seyfert 2 galaxy NGC 2110 obtained in 2012, when the source was at the highest flux level ever observed, and in 2013, when the source was at a more typical flux level. We include archival observations from other X-ray satellites, namely XMM-Newton, Suzaku, BeppoSAX, Chandra and Swift. Simultaneous NuSTA…
The Gemini NICI Planet-Finding Campaign: asymmetries in the HD 141569 disc
Kuchner, Marc J.; Wahhaj, Zahed; Biller, Beth A. +8 more
We report here the highest resolution near-IR imaging to date of the HD 141569A disc taken as part of the NICI (near infrared coronagraphic imager) Science Campaign. We recover four main features in the NICI images of the HD 141569 disc discovered in previous Hubble Space Telescope (HST) imaging: (1) an inner ring/spiral feature. Once deprojected,…
Constraining the galaxy mass content in the core of A383 using velocity dispersion measurements for individual cluster members
Zitrin, A.; Grillo, C.; Balestra, I. +14 more
We use velocity dispersion measurements of 21 individual cluster members in the core of Abell 383, obtained with Multiple Mirror Telescope Hectospec, to separate the galaxy and the smooth dark halo (DH) lensing contributions. While lensing usually constrains the overall, projected mass density, the innovative use of velocity dispersion measurement…