Showing 2000 · astro-phShow all

12 papers · 2 filters

astro-ph2000★ 64 cited

Reanalysis of the high energy cutoff of the 1997 Mkn 501 TeV energy spectrum

HEGRA Collaboration, F. Aharonian

Data taken with the HEGRA system of imaging atmospheric Cherenkov telescopes during the 1997 flares of Mkn 501 are reanalyzed using an algorithm providing improved energy resolutio…

astro-ph2000★ 15 cited

Optical photometry of the UCM Lists I and II. II-B band surface photometry and morphological discussion

P. G. Perez-Gonzalez, J. Gallego, J. Zamorano +1

We present Johnson B surface photometry for the UCM Survey galaxies. One-dimensional bulge-disk decomposition is attempted, discussing on fitting functions and computational proced…

astro-ph2000★ 67 cited

The TeV Energy Spectrum of Mkn 501 Measured with the Stereoscopic Telescope System of HEGRA during 1998 and 1999

The HEGRA Collaboration, F. Aharonian, A. Akhperjanian +1

During 1997, the BL Lac object Mkn 501 went into an extraordinary state of high X-ray and TeV gamma-ray activity, lasting more than 6 months. In this paper we report on the TeV emi…

astro-ph2000

Mapping the star formation history of Mrk86: II. Stellar populations and global interpretation

A. Gil de Paz, J. Zamorano, J. Gallego

In this paper, continuation of Gil de Paz et al. (Paper I), we derive the main properties of the stellar populations in the Blue Compact Dwarf galaxy Mrk86. Ages, stellar masses, m…

astro-ph2000★ 19 cited

Mapping the star formation history of Mrk86: I. Data and models

A. Gil de Paz, J. Zamorano, J. Gallego +1

We have obtained optical (BVR, [OIII]5007 and Halpha), near infrared (JHK) imaging and long-slit optical spectroscopy for the Blue Compact Dwarf galaxy Mrk86 (NGC2537). In this pap…

astro-ph2000★ 109 cited

Multiwavelength optical observations of chromospherically active binary systems. III. High resolution echelle spectra from Ca II H&K to Ca II IRT

D. Montes, M. J. Fernandez-Figueroa, E. De Castro +3

This is the third paper of a series aimed at studying the chromosphere of active binary systems using the information provided for several optical spectroscopic features. High reso…

astro-ph2000★ 10 cited

Rejection of the hypothesis that Markarian 501 TeV photons are pure Bose-Einstein condensates

The HEGRA Collaboration, F. Aharonian, A. Akhperjanian +1

The energy spectrum of the Blazar type galaxy Markarian 501 (Mrk 501) as measured by the High-Energy-Gamma-Ray Astronomy (HEGRA) air Cerenkov telescopes extends beyond 16 TeV and c…

astro-ph2000

Ambipolar Filamentation of Turbulent Magnetic Fields : A numerical simulation

M. Franqueira, M. Tagger, A. I. Gomez de Castro

We present the results of a 2-D, two fluid (ions and neutrals) simulation of the ambipolar filamentation process, in which a magnetized, weakly ionized plasma is stirred by turbule…

astro-ph2000★ 94 cited

The Energy Spectrum of TeV Gamma-Rays from the Crab Nebula as measured by the HEGRA system of imaging air Cherenkov telescopes

F. Aharonian, The HEGRA Collaboration

The Crab Nebula has been observed by the HEGRA (High-Energy Gamma-Ray Astronomy) stereoscopic system of imaging air Cherenkov telescopes (IACTs) for a total of about 200 hrs during…

astro-ph2000★ 31 cited

Star formation properties of UCM galaxies

A. Gil de Paz, A. Aragon-Salamanca, J. Gallego +3

We present new near-infrared J and K imaging data for 67 galaxies from the Universidad Complutense de Madrid survey used to determine the SFR density of the local universe by Galle…

astro-ph2000★ 79 cited

Correlated intense X-ray and TeV activity of Mrk~501 in 1998 June

Rita M. Sambruna

We present exactly simultaneous X-ray and TeV monitoring with {\it RXTE} and HEGRA of the TeV blazar Mrk 501 during 15 days in 1998 June. After an initial period of very low flux a…

astro-ph2000★ 3 cited

Ammonia observations of the nearby molecular cloud MBM 12

Jose F. Gomez, Joaquin Trapero, Sergio Pascual +3

We present NH3(1,1) and NH3(2,2) observations of MBM 12, the closest known molecular cloud (65 pc distance), aimed to find evidence for on-going star formation processes. No local…