First INTEGRAL observations of GRS 1915+105

D. C. Hannikainen; O. Vilhu; J. Rodriguez; S. Brandt; N. J. Westergaard; N. Lund; I. Mocoeur; Ph. Durouchoux; T. Belloni; A. Castro-Tirado; P. A. Charles; A. J. Dean; R. P. Fender; M. Feroci; P. Hakala; R. W. Hunstead; C. R. Kaiser; A. King; I. F. Mirabel; G. G. Pooley; J. Poutanen; K. Wu; A. A. Zdziarski

doi:10.1051/0004-6361:20031444

Home/Archive/arXiv

arXiv · astro-ph/0309532

First INTEGRAL observations of GRS 1915+105

View original source ↗Read source document ↗Export metadata ↓

Abstract

We present data from the first of six monitoring Open Time observations of GRS 1915+105 undertaken with the orbiting INTEGRAL satellite. The source was clearly detected with all three X-ray and gamma-ray instruments on board. GRS 1915+105 was in a highly variable state, as demonstrated by the JEM X-2 and ISGRI lightcurves. These and simultaneous RXTE/PCA lightcurves point to a novel type of variability pattern in the source. In addition, we fit the combined JEM X-2 and ISGRI spectrum between 3-300 keV with a disk blackbody + powerlaw model leading to typical parameter values found earlier at similar luminosity levels. A new transient, IGR J19140+098, was discovered during the present observation.

Explore related subjects

astro-ph

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

D. C. Hannikainen, O. Vilhu, J. Rodriguez, S. Brandt, N. J. Westergaard, N. Lund, I. Mocoeur, Ph. Durouchoux, T. Belloni, A. Castro-Tirado, P. A. Charles, A. J. Dean, R. P. Fender, M. Feroci, P. Hakala, R. W. Hunstead, C. R. Kaiser, A. King, I. F. Mirabel, G. G. Pooley, J. Poutanen, K. Wu, A. A. Zdziarski. 2003-09-19. First INTEGRAL observations of GRS 1915+105. https://doi.org/10.1051/0004-6361%3A20031444

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2020

Cosmic Variance and Its Effect on the Luminosity Function Determination in Deep High z Surveys

We study cosmic variance in deep high redshift surveys and its influence on the determination of the luminosity function for high redshift galaxies. For several survey geometries relevant for HST and JWST instruments, we characterize the distribution of the galaxy number counts. This is obtained by means of analytic estimates via the two point correlation function in extended Press-Schechter theory as well as by using synthetic catalogs extracted from N-body cosmological simulations of structure formation. We adopt a simple luminosity - dark halo mass relation to investigate the environment effects on the fitting of the luminosity function. We show that in addition to variations of the normalization of the luminosity function, a steepening of its slope is also expected in underdense fields, similarly to what is observed within voids in the local universe. Therefore, to avoid introducing artificial biases, caution must be taken when attempting to correct for field underdensity, such as in the case of HST UDF i-dropout sample, which exhibits a deficit of bright counts with respect to the average counts in GOODS. A public version of the cosmic variance calculator based on the two point correlation function integration is made available on the web.

astro-ph↗

arXiv2020

Receiver control for the Submillimeter Array

Efficient operation of a submillimeter interferometer requires remote (preferably automated) control of mechanically tuned local oscillators, phase-lock loops, mixers, optics, calibration vanes and cryostats. The present control system for these aspects of the Submillimeter Array (SMA) will be described. Distributed processing forms the underlying architecture and the software is split between hardware platforms in a leader/follower arrangement. In each antenna cabin, a serial network of up to ten independent 80C196 microcontroller boards attaches to the real-time PowerPC computer (running LynxOS). A multi-threaded, gcc-compiled leader program on the PowerPC accepts top-level requests via remote procedure calls (RPC), subsequently dispatches tuning commands to the relevant follower microcontrollers, and regularly reports the system status to optical-fiber-based reflective memory for common access by the telescope monitor and error reporting system. All serial communication occurs asynchronously via encoded, variable-length packets. The microcontrollers respond to the requested commands and queries by accessing non-volatile, rewriteable lookup-tables (when appropriate) and executing embedded software that operates additional electronic devices (DACs, ADCs, etc.). Since various receiver hardware components require linear or rotary motion, each microcontroller also implements a position servo via a one-millisecond interrupt service routine which drives a DC-motor/encoder combination that remains standard across each subsystem.

astro-ph↗

arXiv2019

Classical analysis of the rotational dynamic of spiral galaxies: Quo Vadis Dark Matter?

In this paper we study a stellar dynamic model for the stars' rotational-dynamics, with a distribution of its own mass, rotating around its center with a higher density, like spiral galaxies happen, by means of a classical calculus of the rotation velocities of a particle around its rotational axis, inside a smoothed distribution of matter. The stars are supposed to be particles and their distribution in the galaxy is modelled as a matter distribution inversely proportional to its distance from its center. Two kinds of matter distribution are supposed: one with constant density, and other with radial distribution. Two types of galaxy symmetry are also considered: spherical and oblate ellipsoidal. Using only classical mechanics arguments it is shown that the calculated velocity distribution inside the galaxy is similar to that obtained from astronomical observations, without the necessity of suppose the existence of dark matter or other phenomena.

astro-ph↗