Search Publications
XMM-Newton observations of four high mass X-ray binaries and IGR J17348-2045
Campana, S.; Stella, L.; Paltani, S. +5 more
We present the results of the XMM-Newton observations of five hard X-ray emitters: IGR J08262-3736, IGR J17354-3255, IGR J16328-4726, SAX J1818.6-1703, and IGR J17348-2045. The first source is a confirmed supergiant high mass X-ray binary, the following two are candidates supergiant fast X-ray transients, SAX J1818.6-1703 is a confirmed supergiant…
Exploring the Relation between (Sub-)Millimeter Radiation and γ-Ray Emission in Blazars with Planck and Fermi
Lähteenmäki, A.; Polenta, G.; Gasparrini, D. +5 more
The coexistence of Planck and Fermi satellites in orbit has enabled the exploration of the connection between the (sub-)millimeter and γ-ray emission in a large sample of blazars. We find that the γ-ray emission and the (sub-)mm luminosities are correlated over five orders of magnitude, L γvpropL (sub-)mm. However, this corre…
The ancient stellar population of M 32: RR Lyrae variable stars confirmed
Saha, A.; Clementini, G.; Contreras Ramos, R. +2 more
Using archival multi-epoch ACS/WFC images in the F606W and F814W filters of a resolved stellar field in Local Group dwarf elliptical galaxy M 32 we have made an accurate colour-magnitude diagram and a careful search for RR Lyr variable stars. We identified 416 bona fide RR Lyr stars over our field of view, and their spatial distribution shows a ri…
Comoving Space Density and Obscured Fraction of High-redshift Active Galactic Nuclei in the Subaru/XMM-Newton Deep Survey
Ueda, Yoshihiro; Akiyama, Masayuki; Hiroi, Kazuo +1 more
We study the comoving space density of X-ray-selected luminous active galactic nuclei (AGNs) and the obscured AGN fraction at high redshifts (3 < z < 5) in the Subaru/XMM-Newton Deep Survey field. From an X-ray source catalog with high completeness of optical identification thanks to deep optical images, we select a sample of 30 AGNs at z &g…
The horizontal branch luminosity vs. metallicity in M 31 globular clusters
Cacciari, C.; Bellazzini, M.; Galleti, S. +3 more
Context. Thanks to the outstanding capabilites of the HST, our current knowledge about the M 31 globular clusters (GCs) is similar to our knowledge of the Milky Way GCs in the 1960s - 1970s, which set the basis for studying the halo and galaxy formation using these objects as tracers, and established their importance in defining the cosmic distanc…
A Physical Model for SN 2001ay, a Normal, Bright, Extremely Slow Declining Type Ia Supernova
Wang, L.; Baron, E.; Dominguez, I. +5 more
We present a study of the peculiar Type Ia supernova 2001ay (SN 2001ay). The defining features of its peculiarity are high velocity, broad lines, and a fast rising light curve, combined with the slowest known rate of decline. It is one magnitude dimmer than would be predicted from its observed Δm 15, and shows broad spectral features. W…
Timing properties of gamma-ray bursts detected by SPI-ACS detector onboard INTEGRAL
Savchenko, V.; Courvoisier, T. J. -L.; Neronov, A.
Aims: We study timing properties of a large sample of gamma-ray bursts (GRB) detected by the anti-coincidence shield (ACS) of the SPI spectrometer of INTEGRAL telescope.
Methods: We identify GRB-like events in the SPI-ACS data. The data set under investigation is the history of count rate of the SPI-ACS detector recorded with a binning o…
Narrow absorption features in the co-added XMM-Newton RGS spectra of isolated neutron stars
Haberl, F.; Neuhäuser, R.; de Vries, C. P. +2 more
We co-added the available XMM-Newton Reflection Grating Spectrometer (RGS) spectra for each of the isolated X-ray pulsars RX J0720.4-3125, RX J1308.6+2127 (RBS1223), RX J1605.3+3249 and RX J1856.4-3754 (four members of the 'Magnificent Seven') and the 'Three Musketeers' Geminga, PSR B0656+14 and PSR B1055-52. We confirm the detection of a narrow a…
A new automatic method to identify galaxy mergers - I. Description and application to the Space Telescope A901/902 Galaxy Evolution Survey
Bell, Eric F.; Wolf, Christian; Aragón-Salamanca, Alfonso +10 more
We present a new automatic method to identify galaxy mergers using the morphological information contained in the residual images of galaxies after the subtraction of a smooth Sérsic model. The removal of the bulk signal from the host galaxy light is done with the aim of detecting the much fainter and elusive minor mergers. The specific morphologi…
Spectrophotometric investigation of Phobos with the Rosetta OSIRIS-NAC camera and implications for its collisional capture
Sierks, H.; Pajola, M.; Barbieri, C. +11 more
The Martian satellite Phobos has been observed on 2007 February 24 and 25, during the pre- and post-Mars closest approach (CA) of the ESA Rosetta spacecraft Mars swing-by. The goal of the observations was the determination of the surface composition of different areas of Phobos, in order to obtain new clues regarding its nature and origin. Near-ul…