The X - Ray È Faint Early - Type Galaxy Ngc 4697
نویسندگان
چکیده
We analyze archival ROSAT HRI, ROSAT PSPC, and ASCA data of the X-rayÈfaint early-type galaxy NGC 4697. The joint ROSAT PSPC]ASCA spectrum is Ðtted by a two-component thermal model, a MEKAL model with keV with low metallicity and a bremsstrahlung kT MEKAL \ 0.26 ~0.03 `0.04 model with keV. A similar model was found to Ðt the spectra of another faint earlykT BREM \ 5.2 ~1.6 `3.0 type galaxy (NGC 4382) and the bulge of M31. We interpret this soft emission as a combination of emission from a soft component of low-mass X-ray binaries (LMXBs) and from a low-temperature interstellar medium, although the relative contributions of the two components could not be determined. Twelve point sources were identiÐed within 4@ of NGC 4697, of which 11 are most likely LMXBs associated with the galaxy. The soft X-ray colors of four of the LMXBs in NGC 4697 support the claim that LMXBs possess a soft spectral component. Finally, we present a simulation of what we believe the Chandra data of NGC 4697 will look like. Subject headings : binaries : close È galaxies : elliptical and lenticular, cD È galaxies : ISM È X-rays : galaxies È X-rays : ISM È X-rays : stars
منابع مشابه
Faint Early - Type Galaxy Ngc 4697
We analyze archival ROSAT HRI, ROSAT PSPC, and ASCA data of the X-ray faint early-type galaxy NGC 4697. The joint ROSAT PSPC + ASCA spectrum is fit by a two-component thermal model, a MEKAL model with kTMEKAL = 0.26 +0.04 −0.03 keV with low metallicity and a bremsstrahlung model with kTBREM = 5.2 +3.0 −1.6 keV. A similar model was found to fit the spectra of another faint early-type galaxy (NGC...
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