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

The supermassive black hole Sgr A* is located at the Milky Way center. Westudied its flaring activity close to the DSO/G2 pericenter passage toconstrain the physical properties and origin of the flares.Simultaneous/coordinated observations were made in 2014 Feb-Apr withXMM-Newton, HST/WFC3, VLT/SINFONI, VLA and CARMA. We detected 2 X-ray and 3 NIRflares on Mar. 10 and Apr. 2 with XMM-Newton and HST and 2 NIR flares on Apr. 3and 4 with VLT. The Mar. 10 X-ray flare has a long rise and a rapid decay. ItsNIR counterpart peaked 4320s before the X-ray peak implying a variation in theX-ray-to-NIR flux ratio. This flare may be a single flare where change in theflux ratio is explained by the adiabatic compression of a plasmon or 2 closeflares with simultaneous X-ray/NIR peaks. We observed an increase in the risingradio flux density on Mar. 10 with the VLA. It could be the delayed emissionfrom a NIR/X-ray flare preceding our observation. The Apr. 2 X-ray flareoccurred for HST in the Earth occultation of Sgr A*. We thus only observed thestart of its NIR counterpart. After the occultation, we observed the decayphase of a bright NIR flare with no X-ray counterpart. On Apr. 3, 2 CARMAflares were observed. The 1rst one may be the delayed emission of a VLT NIRflare. We thus observed 7 NIR flares whose 3 have an X-ray counterpart. Westudied the physical parameters of the flaring region for each NIR flare butnone of the possible radiative processes can be ruled out for the X-ray flarescreation. Our X-ray flaring rate is consistent with those observed in the 2012Chandra XVP campaign. No increase in the flaring activity was thus triggeredclose to the DSO/G2 pericenter passage. Moreover, higher X-ray flaring rateshad already been observed with no increase in the quiescent level. There isthus no direct link between an X-ray flaring-rate increase and anaccretion-rate change. (abridged)

Multiwavelength study of the flaring activity of Sgr A* in 2014 February-April