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 Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

While waiting for new gamma-ray burst detections, the Burst Alert Telescope(BAT) on board Swift covers each day ~50% of the sky in the hard X-ray band(``Survey data''). The large field of view (FOV), high sensitivity and goodangular resolution make BAT a potentially powerful all-sky hard X-ray monitor,provided that mask--related systematics can be properly accounted for. We havedeveloped and tested a complete procedure entirely based on public Swift/BATsoftware tools to analyse BAT Survey data, aimed at assessing the flux andspectral variability of bright sources in the 15-150 keV energy range. Detailedtests of the capabilities of our procedure were performed focusing, inparticular, on the reliability of spectral measurements over the entire BATFOV. First, we analyzed a large set of Crab observations, spread over ~7months. Next, we studied the case of GRO J1655-40, a strongly variable source,which experienced a 9-month long outburst, beginning on February 2005. Such anoutburst was systematically monitored with the well-calibrated PCA and HEXTEinstruments on board the RXTE mission. Thanks to the good BAT temporal coverageof the source, we have been able to cross-check BAT light-curves withsimultaneous HEXTE ones. The Crab tests have shown that our procedure recoversboth the flux and the source spectral shape over the whole FOV of the BATinstrument. Moreover, by cross-checking GRO J1655-40 light-curves obtained byBAT and HEXTE, we found the spectral and flux evolution of the outburst to bein very good agreement. Using our procedure, BAT reproduces HEXTE fluxes withina 10-15% uncertainty with a 3sigma sensitivity of ~20 mCrab for an on-axissource, thus establishing its capability to monitor the evolution of relativelybright hard X-rays sources.

Using GRO J1655-40 to test Swift/BAT as a monitor for bright hard X-ray sources