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BEGIN:VEVENT
DTSTART;TZID=Atlantic/Canary:20231026T103000
DTEND;TZID=Atlantic/Canary:20231026T113000
UID:iactalks-1718
X-WR-CALNAME: IAC Talks: Open Astronomy Seminars
X-ORIGINAL-URL: /iactalks/Talks/view/1718
CREATED:2023-10-26T10:30:00+01:00
X-WR-CALDESC: IAC Talks upcomming talks
SUMMARY:Clouds vs Cherenkov telescopes: problems and solutions.
DESCRIPTION:Clouds vs Cherenkov telescopes: problems and solutions.\nDr. Ju
 lian Sitarek\n\nVery-high-energy (VHE >~100 GeV) gamma rays are absorbe
 d in Earth'satmosphere and thus cannot be detected directly on Earth. Thei
 r fluxesare also typically too low to efficiently study them with satellit
 einstruments. A VHE gamma ray entering the atmosphere initiates anelectrom
 agnetic cascade that induces faint flashes of blueishCherenkov light. Such
  flashes can be then detected by ImagingAtmospheric Cherenkov Telescopes r
 egistering images of passage ofindividual gamma rays through the atmospher
 e.The usage of atmosphere as a part of the detector allows us to achievea 
 collection area of gamma rays over two orders of magnitude higherthan the 
 physical size of the detector. But it also introducessystematic errors con
 nected with the atmosphere's transparency. Inparticular, cloud presence du
 ring the observations can significantlyaffect the data. In this seminar I 
 will cover different methods usedto correct the influence of the clouds. I
  will show how lack of such acorrection introduces bias in the energy esti
 mation of gamma rays. Iwill present how the affected images of showers are
  degraded and thuscan be confused with background events, lowering the col
 lection areaof the telescope. Finally, I will show a novel method of corre
 ctingthe influence of the clouds already at the image level, and discussth
 e possibility of measuring the parameters of a cloud directly withthe obse
 rvations by the Cherenkov telescopes.\n \n \n
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