Search Publications
The evolution of H I and C IV quasar absorption line systems at 1.9 < z < 3.2
Carswell, R. F.; Kim, T. -S.; Partl, A. M. +1 more
We have investigated the distribution and evolution of ~3100 intergalactic neutral hydrogen (H i) absorbers with H I column densities log NH I = [12.75,17.0] at 1.9 < z < 3.2, using 18 high resolution, high signal-to-noise quasar spectra obtained from the ESO VLT/UVES archive. We used two sets of Voigt profile fitting analysis, on…
High-rigidity Forbush decreases: due to CMEs or shocks?
Antia, H. M.; Subramanian, P.; Hayashi, Y. +7 more
Aims: We seek to identify the primary agents causing Forbush decreases (FDs) in high-rigidity cosmic rays observed from the Earth. In particular, we ask if these FDs are caused mainly by coronal mass ejections (CMEs) from the Sun that are directed towards the Earth, or by their associated shocks.
Methods: We used the muon data at cutoff …
Integrated spectroscopy of the Herschel Reference Survey. The spectral line properties of a volume-limited, K-band-selected sample of nearby galaxies
Buat, V.; Boselli, A.; Cortese, L. +2 more
We present long-slit integrated spectroscopy of 238 late-type galaxies belonging to the Herschel Reference Survey, a volume-limited sample representative of the nearby universe. This sample has a unique legacy value since it was ideally defined for any statistical study of the multifrequency properties of galaxies spanning a wide range in morpholo…
Uncertainties in water chemistry in disks: An application to TW Hydrae
Pinte, C.; Dent, W. R. F.; Woitke, P. +7 more
Context. This paper discusses the sensitivity of water lines to chemical processes and radiative transfer for the protoplanetary disk around TW Hya. The study focuses on the Herschel spectral range in the context of new line detections with the PACS instrument from the Gas in Protoplanetary Systems project (GASPS).
Aims: The paper presents an…
Testing reflection features in 4U 1705-44 with XMM-Newton, BeppoSAX, and RXTE in the hard and soft states
Santangelo, A.; Belloni, T.; Robba, N. R. +10 more
We use data from the bright atoll source 4U 1705-44 taken with XMM-Newton, BeppoSAX, and RXTE both in the hard and in the soft state to perform a self-consistent study of the reflection component in this source. Although the data from these X-ray observatories are not simultaneous, the spectral decomposition is shown to be consistent among the dif…
A solar tornado triggered by flares?
Innes, D. E.; Low, B. C.; Tiwari, S. K. +1 more
Context. Solar tornados are dynamical, conspicuously helical magnetic structures that are mainly observed as a prominence activity.
Aims: We investigate and propose a triggering mechanism for the solar tornado observed in a prominence cavity by SDO/AIA on September 25, 2011.
Methods: High-cadence EUV images from the SDO/AIA and the Ahead…
The virtual observatory service TheoSSA: Establishing a database of synthetic stellar flux standards. I. NLTE spectral analysis of the DA-type white dwarf G191-B2B
Rauch, T.; Werner, K.; Kruk, J. W. +1 more
Context. Hydrogen-rich, DA-type white dwarfs are particularly suited as primary standard stars for flux calibration. State-of-the-art NLTE models consider opacities of species up to trans-iron elements and provide reliable synthetic stellar-atmosphere spectra to compare with observations.
Aims: We will establish a database of theoretical spec…
Unveiling the nature of INTEGRAL objects through optical spectroscopy. X. A new multi-year, multi-observatory campaign
Palazzi, E.; Minniti, D.; Masetti, N. +18 more
Within the framework of our program (running since 2004) of identification of hard X-ray INTEGRAL sources through optical spectroscopy, we present the results concerning the nature of 33 high-energy objects. The data were acquired with the use of six telescopes of different sizes and from one on-line archive. The results indicate that the majority…
X-ray spectral variability of seven LINER nuclei with XMM-Newton and Chandra data
González-Martín, O.; Márquez, I.; Masegosa, J. +1 more
Context. One of the most distinctive features in active galactic nuclei (AGN) is the variability of their emission. Variability has been discovered at X-ray, UV, and radio frequencies on timescales from hours to years. Among the AGN family and according to theoretical studies, low-ionization nuclear emission line region (LINER) nuclei would be obj…
Mid- to far-infrared properties of star-forming galaxies and active galactic nuclei
Elbaz, D.; Morrison, G.; Helou, G. +19 more
We study the mid- to far-IR properties of a 24 µm-selected flux-limited sample (S24> 5 mJy) of 154 intermediate redshift (⟨ z ⟩ ~ 0.15), infrared luminous galaxies, drawn from the 5 Milli-Jansky Unbiased Spitzer Extragalactic Survey. By combining existing mid-IR spectroscopy and new Herschel SPIRE submm photometry from the Hers…