Search Publications
NuSTAR + XMM-Newton monitoring of the neutron star transient AX J1745.6-2901
Hailey, C.; Stern, D.; Bianchi, S. +12 more
AX J1745.6-2901 is a high-inclination (eclipsing) transient neutron star (NS) low-mass X-ray binary showcasing intense ionized Fe K absorption. We present here the analysis of 11 XMM-Newton and 15 NuSTAR new data sets (obtained between 2013 and 2016), therefore tripling the number of observations of AX J1745.6-2901 in outburst. Thanks to simultane…
Limits on turbulent propagation of energy in cool-core clusters of galaxies
Fabian, A. C.; Reynolds, C. S.; Pinto, C. +2 more
We place constraints on the propagation velocity of bulk turbulence within the intracluster medium of three clusters and an elliptical galaxy. Using Reflection Grating Spectrometer measurements of turbulent line broadening, we show that for these clusters, the 90 per cent upper limit on turbulent velocities when accounting for instrumental broaden…
The star formation history in the M31 bulge
Olsen, Knut; Saha, Abhijit; Dong, Hui +4 more
We present the study of stellar populations in the central 5.5 arcmin (∼1.2 kpc) of the M31 bulge by using the optical colour magnitude diagram derived from the observations taken by HST Advanced Camera for Surveys observations. In order to enhance image quality and then obtain deeper photometry, we construct Nyquist-sampled images and use a decon…
Deep ALMA photometry of distant X-ray AGN: improvements in star formation rate constraints, and AGN identification
Alexander, D. M.; Knudsen, K. K.; Rosario, D. J. +5 more
We present the star formation rates (SFRs) of a sample of 109 galaxies with X-ray-selected active galactic nuclei (AGNs) with moderate to high X-ray luminosities (L_2-8 keV = 10^{42}-10^{45} erg s^{-1}), at redshifts 1 < z < 4.7, that were selected to be faint or undetected in the Herschel bands. We combine our deep Atacama large (sub-)milli…
The parsec-scale relationship between ICO and AV in local molecular clouds
Bolatto, Alberto D.; Leroy, Adam K.; Glover, Simon C. O. +4 more
We measure the parsec-scale relationship between integrated CO intensity (ICO) and visual extinction (AV) in 24 local molecular clouds using maps of CO emission and dust optical depth from Planck. This relationship informs our understanding of CO emission across environments, but clean Milky Way measurements remain scarce. We…
Serendipitous discovery of quadruply imaged quasars: two diamonds
Schechter, Paul L.; Anguita, T.; Lucey, John R. +1 more
Gravitationally lensed quasars are powerful and versatile astrophysical tools, but they are challengingly rare. In particular, only ∼25 well-characterized quadruple systems are known to date. To refine the target catalogue for the forthcoming Taipan Galaxy Survey, the images of a large number of sources are being visually inspected in order to ide…
The variability of the warm absorber in I Zwicky 1 as seen by XMM-Newton
Brandt, W. N.; Kriss, G. A.; Costantini, E. +4 more
We present new XMM-Newton observations of the intriguing warm absorber in I Zwicky 1. This luminous and nearby narrow-line Seyfert 1 galaxy shows ionized absorption by two components of outflowing gas; a low and a high-ionization phase with log ξ ∼ 0 and log ξ ∼ 2, respectively. Detailed modelling of these data reveal a complex and variable multip…
An X-ray view of central engines of low-luminosity quasars (LLQSO) in the local Universe
Guainazzi, Matteo; Laha, Sibasish; Markowitz, Alex G. +1 more
We have carried out a systematic X-ray spectral analysis of a sample of low-luminosity quasars (LLQSO) to investigate the nature of the central engines of these sources. The optically selected LLQSO sample consists of close, known bright active galactic nuclei (AGN) which serves as an important link between the powerful quasars at higher redshift …
Ultraviolet stellar population of the old open cluster M67 (NGC 2682)
Subramaniam, Annapurni; Sindhu, N.; Radha, C. Anu
We present the results of ultraviolet (UV) photometry of the old open cluster M67 obtained using Galaxy Evolution Explorer in far-ultraviolet (FUV) and near-ultraviolet (NUV) bands. UV detections of 18 blue straggler stars (BSSs), 3 white dwarfs (WDs), 4 yellow straggler stars, 2 sub-subgiants, and 25 X-ray sources are presented (along with an onl…
A bright-lensed galaxy at z = 5.4 with strong Ly α emission
Fan, Xiaohui; Jiang, Linhua; McGreer, Ian D. +10 more
We present a detailed study of an unusually bright, lensed galaxy at z = 5.424 discovered within the CFHTLS imaging survey. With an observed flux of iAB = 23.0, J141446.82+544631.9 is one of the brightest galaxies known at z > 5. It is characterized by strong Ly α emission, reaching a peak in (observed) flux density of >10-16…