iLdX-SFR relation in star-forming galaxies

We compare the results of Grimm, Gilfanov & Sunyaev and Ranalli, Comastri & Seti on the iLdX-SFR (X-ray luminosity-star formation rate) relation in normal galaxies. Based on the iLdX-stellar mass dependence for low-mass X-ray binaries (LMXBs), we show that low-SFR ( ?1 Md ? yr super -1) gala...

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Bibliographic Details
Published in:Monthly notices of the Royal Astronomical Society 2004-01, Vol.347 (3), p.L57-L60
Main Authors: Gilfanov, M, Grimm, H.-J., Sunyaev, R
Format: Article
Language:English
Online Access:Get full text
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Summary:We compare the results of Grimm, Gilfanov & Sunyaev and Ranalli, Comastri & Seti on the iLdX-SFR (X-ray luminosity-star formation rate) relation in normal galaxies. Based on the iLdX-stellar mass dependence for low-mass X-ray binaries (LMXBs), we show that low-SFR ( ?1 Md ? yr super -1) galaxies in the Ranalli et al. sample are contaminated by the X-ray emission from LMXBs, unrelated to the current star formation activity. However, the most important conclusion from our comparison is that, after the data are corrected for the `LMXB contamination', the two data sets become consistent with each other, despite differences in their content, variability effects, adopted source distances, X-ray fluxes and SFR determinations, and also in the cosmological parameters used in interpreting the Hubble Deep Field North (HDF-N) data. They also agree well, both in the low- and high-SFR regimes, with the predicted iLdX-SFR dependence derived from the parameters of the `universal' high-mass X-ray binary (HMXB) luminosity function. This encouraging result emphasizes the potential of the X-ray luminosity as an independent SFR indicator for normal galaxies.
ISSN:0035-8711