Search Publications
Quasi Periodic Oscillations in Blazars
Gupta, Alok C.
Here we report our recent discoveries of Quasi-Periodic Oscillations (QPOs) in blazars time series data in X-ray and optical electromagnetic bands. Any such detection can give important clue of the location and nature of the processes of emission mechanism. In the case of radio-quiet AGN, the detected QPOs are very likely to be associated with the…
Archival legacy investigations of circumstellar environments: overview and first results
Schneider, Glenn; Hines, Dean C.; Perrin, Marshall D. +12 more
We are currently conducting a comprehensive and consistent re-processing of archival HST-NICMOS coronagraphic surveys using advanced PSF subtraction methods, entitled the Archival Legacy Investigations of Circumstellar Environments program (ALICE, HST/AR 12652). This virtual campaign of about 400 targets has already produced numerous new detection…
Drainage systems of Lonar Crater, India: Contributions to Lonar Lake hydrology and crater degradation
Sekine, Yasuhito; Matsui, Takafumi; Komatsu, Goro +3 more
Lonar, a 1.8-km-diameter impact crater in India, is a rare example of terrestrial impact craters formed in basaltic bedrock. The estimated age of the crater ranges widely from less than 12 ka to over 600 ka, but the crater preserves a relatively pristine morphology. We conducted a study of various drainage systems of Lonar Crater. The crater floor…
Modeling the microphysics of CO2 ice clouds within wave-induced cold pockets in the martian mesosphere
Montmessin, F.; Spiga, A.; Lefèvre, F. +2 more
Mesospheric CO2 ice clouds on Mars are simulated with a 1D microphysical model, which includes a crystal growth rate adapted to high supersaturations encountered in the martian mesosphere. Observational constraints (crystal radius and opacity) exist for these clouds observed during the day around the equator at ∼60-80 km altitude. Night…
Halo Mass Dependence of H I and O VI Absorption: Evidence for Differential Kinematics
Kacprzak, Glenn G.; Churchill, Christopher W.; Nielsen, Nikole M. +4 more
We studied a sample of 14 galaxies (0.1 < z < 0.7) using HST/WFPC2 imaging and high-resolution HST/COS or HST/STIS quasar spectroscopy of Lyα, Lyβ, and O VI λλ1031, 1037 absorption. The galaxies, having 10.8 <= log (M h/M ⊙) <= 12.2, lie within D = 300 kpc of quasar sightlines, probing out to D/R vir =…
The pointing system of the Herschel space observatory. Description, Calibration, Performance and improvements
Marston, Anthony; Linz, Hendrik; Merín, Bruno +13 more
We present the activities carried out to calibrate and characterise the performance of the elements of attitude control and measurement on board the Herschel spacecraft. The main calibration parameters and the evolution of the indicators of the pointing performance are described, from the initial values derived from the observations carried out in…
HerMES: Spectral Energy Distributions of Submillimeter Galaxies at z > 4
Bock, J. J.; Clements, D. L.; Burgarella, D. +20 more
We present a study of the infrared properties for a sample of seven spectroscopically confirmed submillimeter galaxies (SMGs) at z > 4.0. By combining ground-based near-infrared, Spitzer IRAC and MIPS, Herschel SPIRE, and ground-based submillimeter/millimeter photometry, we construct their spectral energy distributions (SEDs) and a composite mo…
The NUV-r versus Mr Plane as a Tracer of Early-type Galaxy Evolution in the USGC U376 and LGG 225 Groups
Mazzei, Paola; Rampazzo, Roberto; Marino, Antonietta
With the aim of tracing back the evolution of galaxies in nearby groups, we use smooth particle hydrodynamical (SPH) simulations with chemo-photometric implementation. Here, we focus on the evolution of the early-type members (Es and S0s; ETGs hereafter) in two groups, USGC U376 and LGG 225, both in the Leo cloud. We use the near-UV (NUV)-optical …
Fermi-LAT Observations of Supernova Remnants Kesteven 79
Auchettl, Katie; Slane, Patrick; Castro, Daniel
In this paper, we report on the detection of γ-ray emission coincident with the Galactic supernova remnant (SNR) Kesteven 79 (Kes 79). We analyzed approximately 52 months of data obtained with the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. Kes 79 is thought to be interacting with adjacent molecular clouds, based on the pres…
Accounting for Cosmic Variance in Studies of Gravitationally Lensed High-redshift Galaxies in the Hubble Frontier Field Clusters
Ellis, Richard S.; Robertson, Brant E.; Dunlop, James S. +3 more
Strong gravitational lensing provides a powerful means for studying faint galaxies in the distant universe. By magnifying the apparent brightness of background sources, massive clusters enable the detection of galaxies fainter than the usual sensitivity limit for blank fields. However, this gain in effective sensitivity comes at the cost of a redu…