Abstract
We present the first results of an XMM-Newton EPIC survey of NGC 2516, a southern low-metallicity open cluster with an age close to the Pleiades. The attained limiting sensitivity is of ~2.4 10-15 erg s-1 cm-2 in the 0.1-4.0 keV bandpass. This has been achieved by summing the data of the MOS and PN cameras of two distinct observations for a total exposure time of ~33 ks and by analyzing the summed data set with the wavelet detection algorithm developed at Osservatorio Astronomico di Palermo (OAPA) that has yielded over 200 X-ray detections. Using data just from a single exposure or from a single camera would have reduced by a factor 2-4 our limiting sensitivity and would have resulted in 25-40% less X-ray detections. To date, 129 detections have as counterparts one or more of the 540 photometrically selected cluster members in the surveyed region, for a total of 147 likely detected members, with unique identification in 112 cases. We derive the X-ray luminosity functions (XLF) of NGC 2516 members of different spectral types and compare them with those of the more metal rich, approximately coeval Pleiades cluster, finding the NGC 2516 photometrically selected dG and dK stars less luminous than the Pleiades. The XLFs of the NGC 2516 and of the Pleiades dM stars are indistinguishable. We compare the XMM-Newton results with those recently obtained with Chandra .
Highlights
NGC 2516 has been chosen as an XMM-Newton calibration target in order to “bore sight” the alignment of the X-ray telescope as well as the relative positions of the EPIC cameras CCDs since it is a region rich of X-ray emitting young stars
In the case of B, dA, and dG stars we have not found statistical significant difference between the X-ray luminosity functions (XLF) derived over the entire XMM-Newton FOV and those derived from Chandra data (Harnden et al 2000), while we have found an indication of difference in the cases of dF and dM stars, and a clear difference in the case of dK stars, but, as we explain below, field star contamination can be a plausible explanation for these findings
NGC 2516 was chosen as a calibration target in order to “bore sight” the alignment of the X-ray telescope with the XMM-Newton detectors, this cluster is of particular scientific interest since, being metal-poor with respect to the Sun, it allows us to explore the effect of metallicity on coronal emission level
Summary
NGC 2516 has been chosen as an XMM-Newton calibration target in order to “bore sight” the alignment of the X-ray telescope as well as the relative positions of the EPIC cameras CCDs since it is a region rich of X-ray emitting young stars. Apart from this role in the early phase of the XMM-Newton mission, NGC 2516 plays an important role in the study of stellar physics. Our paper is organized as follows: in Sect. 3 we will describe the results we have obtained and in Sect. Our paper is organized as follows: in Sect. 2 we will describe the X-ray data and analysis, in Sect. 3 we will describe the results we have obtained and in Sect. 4 we will summarize and discuss our findings.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call