Search Publications
XMM-Newton observations of the merging galaxy cluster CIZA J2242.8+5301
Simionescu, A.; Croston, J. H.; Brüggen, M. +4 more
We studied the intracluster medium (ICM) of the galaxy cluster CIZA J2242.8+5301 using deep XMM-Newton observations. The cluster hosts a remarkable 2 Mpc long, ∼50 kpc wide radio relic that has been nicknamed the `Sausage'. A smaller, more irregular counter relic is also present, along with a faint giant radio halo. We analysed the distribution of…
The Mass-Metallicity Relation of a z ~ 2 Protocluster with MOSFIRE
Shapley, Alice E.; Steidel, Charles C.; Reddy, Naveen A. +7 more
We present Keck/MOSFIRE observations of the role of environment in the formation of galaxies at z ~ 2. Using K-band spectroscopy of Hα and [N II] emission lines, we have analyzed the metallicities of galaxies within and around a z = 2.3 protocluster discovered in the HS1700+643 field. Our main sample consists of 23 protocluster and 20 field galaxi…
Intensity contrast of solar network and faculae
Solanki, S. K.; Yeo, K. L.; Krivova, N. A.
Aims: This study aims at setting observational constraints on the continuum and line core intensity contrast of network and faculae, specifically, their relationship with magnetic field and disc position.
Methods: Full-disc magnetograms and intensity images by the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observat…
Infrared identification of high-mass X-ray binaries discovered by INTEGRAL
Chaty, S.; Rahoui, F.; Tomsick, J. A. +2 more
Context. Since it started observing the sky, the INTEGRAL satellite has discovered new categories of high mass X-ray binaries (HMXB) in our Galaxy. These observations raise important questions on the formation and evolution of these rare and short-lived objects.
Aims: We present here new infrared observations from which to reveal or constrain…
Further Evidence for a Supermassive Black Hole Mass-Pitch Angle Relation
Bentz, Misty C.; Davis, Benjamin L.; Kennefick, Julia D. +7 more
We present new and stronger evidence for a previously reported relationship between galactic spiral arm pitch angle P (a measure of the tightness of spiral structure) and the mass M BH of a disk galaxy's nuclear supermassive black hole (SMBH). We use an improved method to accurately measure the spiral arm pitch angle in disk galaxies to…
The merger rates and sizes of galaxies across the peak epoch of star formation from the HiZELS survey
Smail, Ian; Sobral, David; Stott, John P. +3 more
We use the HiZELS narrow-band Hα survey in combination with CANDELS, UKIDSS and WIRDS near-infrared imaging, to investigate the morphologies, merger rates and sizes of a sample of Hα emitting galaxies in the redshift range z = 0.40-2.23, an epoch encompassing the rise to the peak of the star formation rate density. Merger rates are estimated from …
The domination of Saturn's low-latitude ionosphere by ring `rain'
Baines, K. H.; Jones, G. H.; Cowley, S. W. H. +5 more
Saturn's ionosphere is produced when the otherwise neutral atmosphere is exposed to a flow of energetic charged particles or solar radiation. At low latitudes the solar radiation should result in a weak planet-wide glow in the infrared, corresponding to the planet's uniform illumination by the Sun. The observed electron density of the low-latitude…
Triggering process of electromagnetic ion cyclotron rising tone emissions in the inner magnetosphere
Omura, Yoshiharu; Shoji, Masafumi
Spacecraft observations and simulations show generation of coherent electromagnetic ion cyclotron (EMIC) triggered emissions with rising tone frequencies. In the inner magnetosphere, the spontaneously triggered EMIC waves are generated by the energetic protons with large temperature anisotropy. We reproduced EMIC triggered emissions in the Earth's…
SN 2009ip: Constraints on the Progenitor Mass-loss Rate
Lin, L.; Kouveliotou, C.; Kasliwal, M. M. +4 more
Some supernovae (SNe) show evidence for mass-loss events taking place prior to their explosions. Measuring their pre-outburst mass-loss rates provides essential information regarding the mechanisms that are responsible for these events. Here we present XMM-Newton and Swift X-ray observations taken after the latest, and presumably the final, outbur…
Metallicity Differences in Type Ia Supernova Progenitors Inferred from Ultraviolet Spectra
Foley, Ryan J.; Kirshner, Robert P.
Two "twin" Type Ia supernovae (SNe Ia), SNe 2011by and 2011fe, have extremely similar optical light-curve shapes, colors, and spectra, yet have different ultraviolet (UV) continua as measured in Hubble Space Telescope spectra and measurably different peak luminosities. We attribute the difference in the UV continua to significantly different proge…