Search Publications
Composite Inflation in the light of 2015 Planck data
Channuie, Phongpichit
In this work, we examine cosmological constraints on models of composite inflation based on the slow-roll approximation by using the recent Planck measurement. We compare the spectral index of curvature perturbation (and its running) and the tensor-to-scalar ratio predicted by such models with Planck 2015 data. We find that the predictions of tech…
Dry Merger Rate and Post-merger Fraction in the Coma Cluster Core
De Propris, Roberto; Jogee, Shardha; Weinzirl, Tim +3 more
We evaluate the dry merger activity in the Coma cluster, using a spectroscopically complete sample of 70 red-sequence (RS) galaxies, most of which (∼75%) are located within 0.2R200 (∼0.5 Mpc) from the cluster center, with data from the Coma Treasury Survey obtained with the Hubble Space Telescope. The fraction of close galaxy pairs in t…
The prolonged southward IMF-Bz event of 2-4 May 1998: Solar, interplanetary causes and geomagnetic consequences
Janardhan, P.; Yan, Y.; Tokumaru, M. +5 more
A detailed investigation is carried out to understand the prolonged (∼44 h) weakly southward interplanetary magnetic field (IMF-Bz) condition during 2-4 May 1998. In situ observations, during the period, show the passage of an expanding magnetic cloud embedded in an interplanetary coronal mass ejection (ICME), followed up by a shock and…
Flight model measurements of the porous plug and film flow suppression system for the ASTRO-H Soft X-ray Spectrometer dewar
Ezoe, Yuichiro; Ishikawa, Kumi; Ohashi, Takaya +9 more
Flight model measurements of a porous plug phase separator and a film flow suppression system for the ASTRO-H Soft X-ray Spectrometer dewar are described. ASTRO-H is the sixth Japanese astronomy satellite and will be launched in 2016. It carries the Soft X-ray Spectrometer consisting of an X-ray optic and an X-ray microcalorimeter system operated …
New temperature and pressure retrieval algorithm for high-resolution infrared solar occultation spectroscopy: analysis and validation against ACE-FTS and COSMIC
Olsen, Kevin S.; Strong, Kimberly; Toon, Geoffrey C. +1 more
Motivated by the initial selection of a high-resolution solar occultation Fourier transform spectrometer (FTS) to fly to Mars on the ExoMars Trace Gas Orbiter, we have been developing algorithms for retrieving volume mixing ratio vertical profiles of trace gases, the primary component of which is a new algorithm and software for retrieving vertica…
High-energy monitoring of Seyfert galaxies: The case of NGC 4593
Bianchi, S.; Cappi, M.; Ponti, G. +6 more
We discuss preliminary results from a joint XMM-Newton and NuSTAR monitoring program on the active galactic nucleus NGC 4593, consisting of 5 × 20 ks observations, spaced by two days, performed in January 2015. The source is found to be variable, both in flux and spectral shape, on time scales as short as a few ks. The spectrum clearly softens whe…
Bright stars observed by FIMS/SPEAR
Edelstein, Jerry; Jo, Young-Soo; Choi, Yeon-Ju +5 more
In this paper, we present a catalogue of the spectra of bright stars observed during the sky survey using the Far-Ultraviolet Imaging Spectrograph (FIMS), which was designed primarily to observe diffuse emissions. By carefully eliminating the contamination from the diffuse background, we obtain the spectra of 70 bright stars observed for the first…
Imaging cosmic polarization rotation
Contaldi, Carlo R.
We introduce a method to isolate the contribution of parity-violating modes to the peak constrained correlation function. This method can be used as a local estimate of polarization rotation. We test this method using simulations and by applying it to Planck maps [P. A. R. Ade et al., arXiv:1502.01589 astro.ph.co]. We obtain a constraint on the mo…
A Road Map for the Generation of a Near-Infrared Guide Star Catalog for Thirty Meter Telescope Observations
Subramaniam, Annapurni; Simard, Luc; Subramanian, Smitha +5 more
The near-infrared instruments in the upcoming Thirty Meter Telescope (TMT) will be assisted by a multi conjugate Adaptive Optics (AO) system. For the efficient operation of the AO system, during observations, a near-infrared guide star catalog which goes as faint as 22 mag in JVega band is essential and such a catalog does not exist. A …
Characterizing elusive, faint dusty star-forming galaxies: a lensed, optically undetected ALMA galaxy at z 3.3
Berta, S.; Daddi, E.; Elbaz, D. +19 more
We present the serendipitous ALMA detection of a faint submillimeter galaxy (SMG) lensed by a foreground z 1 galaxy. By optimizing the source detection to deblend the system, we accurately build the full spectral energy distribution of the distant galaxy from the I814 band to radio wavelengths. It is extremely red, with a I-K colour larger than 2.…