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 the discovery of an X-ray source coincident with the nuclear starcluster at the dynamical center of the nearby late-type spiral galaxy NGC 2403.The X-ray luminosity of this source varies from below detection levels, ~1e35erg/s in the 0.5-8.0 keV band, to 7e38 erg/s on timescales between observationsof less than 2 months. The X-ray spectrum is well-fit by an accretion diskmodel consisting of multiple blackbody components and corresponding physicallyto a compact object mass of greater than approximately 5 solar masses. Nopulsations nor aperiodic behavior is evident in its X-ray light curve on theshort timescales of the individual observations. The X-ray properties of thesource are more similar to those of the nuclear source X-8 in M33, believed tobe a low-mass X-ray binary, then to those of the low-luminosity active galacticnucleus in NGC 4395. The brightness of the nuclear star cluster, M_I ~ -11.8mag, is typical of clusters in late-type spirals but its effective radius, r_e\~ 12 pc, is several times larger than average indicating a relatively relaxedcluster and a low probability of a central massive object. The cluster has amass 3e6 solar masses and an age of 1.4 Gyr estimating from its observed colorsand brightness.Comment: 7 pages, submitted to Ap

Discovery of a Transient X‐Ray Source in the Compact Stellar Nucleus of NGC 2403