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BEGIN:VEVENT
DTSTART;TZID=Atlantic/Canary:20170221T123000
DTEND;TZID=Atlantic/Canary:20170221T133000
UID:iactalks-998
X-WR-CALNAME: IAC Talks: Open Astronomy Seminars
X-ORIGINAL-URL: /iactalks/Talks/view/998
CREATED:2017-02-21T12:30:00+00:00
X-WR-CALDESC: IAC Talks upcomming talks
SUMMARY:Population of red supergiants in dwarf irregular galaxies
DESCRIPTION:Population of red supergiants in dwarf irregular galaxies\nDr. 
 Nikolay Britavskiy\n\nThe identification and investigation of red supergia
 nts (RSGs) in the Local Group and beyond are extremely important for under
 standing massive star evolution and mass-loss.  Star-forming dwarf ir
 regular (dIrr) galaxies serve as ideal laboratories for investigating phys
 ics of red supergiants within the context of different metallicities of ho
 st galaxies. Also, RSGs may be used as tracers for abundance determination
 s and star formation history of dIrrs. I will present a systematic survey 
 of RSGs and luminous blue variables (LBVs) in nearby dIrr galaxies with th
 e goal to complete the census of these objects in the Local Group. Using t
 he fact that RSGs and LBVs are bright in mid-infrared colors due to dust, 
 we applied a technique that allows us to select dusty massive stars based 
 on their [3.6] and [4.5] Spitzer photometry. I applied our criteria to 7 d
 Irr galaxies: Pegasus, Phoenix, Sextans A, Sextans B, WLM, IC 10 and IC 16
 13 selecting 124 point sources, which we observed with the VLT/FORS2, GTC/
 OSIRIS and duPont/WFCCD spectrographs. In total, we identified 28 RSGs (21
  are new discoveries) and 2 new emission line objects in these galaxies. T
 hese new discoveries are statistically significant and this sample increas
 ed the number of spectroscopically confirmed RSGs in dIrrs by 50%. Moreove
 r, for the newly identified RSGs we measured the fundamental physical para
 meters by fitting their observational spectral energy distributions with M
 ARCS stellar atmosphere models. This work serves as a basis for further in
 vestigation (also in a framework of my activity in IAC) of the newly disco
 vered dusty massive stars and their host galaxies.
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