English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We report a detailed spectral analysis of the population of low-mass X-raybinaries (LMXBs) detected in the elliptical galaxy NGC~4278 with Chandra. Sevenluminous sources were studied individually, four in globular clusters (GCs),and three in the stellar field. The range of (0.3-8 keV) $L_X$ for thesesources suggests that they may be black hole binaries (BHBs). Comparison of ourresults with simulations allows us to discriminate between disk and power-lawdominated emission, pointing to spectral/luminosity variability, reminiscent ofGalactic BHBs. The BH masses derived from a comparison of our spectral resultswith the $L_X \sim T^4_{in}$ relation of Galactic BHBs are in the 5-15$M_{\odot}$ range, as observed in the Milky Way.  The analysis of joint spectra of sources selected in three luminosity rangessuggests that while the high luminosity sources have prominent thermal diskemission components, power-law components are likely to be important in the midand low-luminosity spectra. Comparing low-luminosity average spectra, we find arelatively larger $N_H$ in the GC spectrum; we speculate that this may point toeither a metallicity effect, or to intrinsic physical differences between fieldand GC accreting binaries.  Analysis of average sample properties uncover a previously unreported $L_X -R_G$ correlation (where $R_G$ is the galactocentric radius) in the GC-LMXBsample, implying richer LMXB populations in more central GCs. No such trend isseen in the field LMXB sample. We can exclude that the GC $L_X - R_G$correlation is the by-product of a luminosity effect, and suggest that it maybe related to the presence of more compact GCs at smaller galactocentric radii,fostering more efficient binary formation.

Field and Globular Cluster LMXBs in NGC 4278