LX-SFR relation in star-forming galaxies
Abstract
We compare the results of Grimm, Gilfanov & Sunyaev and Ranalli, Comastri & Seti on the LX-SFR (X-ray luminosity-star formation rate) relation in normal galaxies. Based on the LX-stellar mass dependence for low-mass X-ray binaries (LMXBs), we show that low-SFR (<~1 Msolar yr-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 LX-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.- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- January 2004
- DOI:
- 10.1111/j.1365-2966.2004.07450.x
- arXiv:
- arXiv:astro-ph/0301331
- Bibcode:
- 2004MNRAS.347L..57G
- Keywords:
-
- galaxies: starburst;
- X-rays: binaries;
- X-rays: galaxies;
- Astrophysics
- E-Print:
- revised, accepted for publication in MNRAS Letters