Deep X-ray survey of the young open cluster NGC 2516 with XMM-Newton

Free access article

Issue		A&A Volume 450, Number 3, May II 2006


Page(s)		993 - 1004
Section		Galactic structure, stellar clusters, and populations
DOI		http://dx.doi.org/10.1051/0004-6361:20054003

A&A 450, 993-1004 (2006)
DOI: 10.1051/0004-6361:20054003

Deep X-ray survey of the young open cluster NGC 2516 with XMM-Newton

I. Pillitteri¹, G. Micela², F. Damiani² and S. Sciortino²

¹ Università degli Studi di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy
e-mail: pilli@astropa.unipa.it
² INAF - Osservatorio Astronomico di Palermo Piazza del Parlamento 1, 90134 Palermo, Italy
e-mail: [giusi;damiani;sciorti]@astropa.unipa.it

(Received 6 August 2005 / Accepted 6 January 2006 )

Abstract
Aims.We report a deep X-ray survey of the young (~140 Myr), rich open cluster NGC 2516 obtained with the EPIC camera on board the XMM-Newton satellite.
Methods.By combining data from six observations, a high sensitivity, greater than a factor of 5 with respect to recent Chandra observations, has been achieved. Kaplan-Meier estimators of the cumulative X-ray luminosity distribution are built, statistically corrected for non members contaminants and compared to those of the nearly coeval Pleiades. The EPIC spectra of the X-ray brightest stars are fitted using optically thin model plasma with one or two thermal components.
Results.We detected 431 X-ray sources and 234 of them have as optical counterparts cluster stars spanning the entire NGC 2516 Main Sequence. On the basis of X-ray emission and optical photometry, we indicate 20 new candidate members of the cluster; at the same time we find 49 X-ray sources without known optical or infrared counterpart. The X-ray luminosities of cluster stars span the range $\log L_{\rm X}$ (erg s^-1) = 28.4-30.8. The representative temperatures span the 0.3-0.6 keV (3.5-8 MK) range for the cool component and 1.0-2.0 keV (12-23 MK) for the hot one; similar values are found in other young open clusters like the Pleiades, IC 2391, and Blanco 1. While no significant differences are found in X-ray spectra, NGC 2516 solar type stars are definitely less luminous in X-rays than the nearly coeval Pleiades. The comparison with a previous ROSAT survey reveals the lack of variability amplitudes larger than a factor of 2 in solar type stars in a ${\sim} 11$ yr time scale of the cluster and thus activity cycles like in the Sun are probably absent or have a different period and amplitude in young stars.

Key words: X-ray: stars -- stars: activity -- open clusters and associations: individual: NGC 2516

SIMBAD Objects

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.