سمینار این هفته را <آقای احمد مهرابی> برگزار خواهند کرد. عنوان و چکیدهٔ سمینار ایشان به شرح زیر است:
Title:
َA review on papar “Frequency of Solar-Like Systems and of Ice and Gas Giants Beyond the Snow Line from High-Magnification Microlensing Events in 2005-2008.
We present the first measurement of planet frequency beyond the “snow line” for planet/star mass-ratios[-4.5<log q<-2]: d^2 N/dlog q/dlog s=(0.36+-0.15)/dex^2 at mean mass ratio q=5e-4, and consistent with being flat in log projected separation, s. Our result is based on a sample of 6 planets detected from intensive follow-up of high-mag (A>200) microlensing events during 2005-8. The sample host stars have typical mass M_host 0.5 Msun, and detection is sensitive to planets over a range of projected separations (R_E/s_max,R_E*s_max), where R_E 3.5 AU sqrt(M_host/Msun) is the Einstein radius and s_max (q/5e-5)^{2/3}, corresponding to deprojected separations ~3 times the “snow line”. Though frenetic, the observations constitute a “controlled experiment”, which permits measurement of absolute planet frequency. High-mag events are rare, but the high-mag channel is efficient: half of high-mag events were successfully monitored and half of these yielded planet detections. The planet frequency derived from microlensing is a factor 7 larger than from RV studies at factor ~25 smaller separations [2<P<2000 days]. However, this difference is basically consistent with the gradient derived from RV studies (when extrapolated well beyond the separations from which it is measured). This suggests a universal separation distribution across 2 dex in semi-major axis, 2 dex in mass ratio, and 0.3 dex in host mass. Finally, if all planetary systems were “analogs” of the Solar System, our sample would have yielded 18.2 planets (11.4 “Jupiters”, 6.4 “Saturns”, 0.3 “Uranuses”, 0.2 “Neptunes”) including 6.1 systems with 2 or more planet detections. This compares to 6 planets including one 2-planet system in the actual sample, implying a first estimate of 1/6 for the frequency of solar-like systems.
این سمینار در روز <یکشنبه> <11 مهر 1389> در ساعت <15> در امفی تئاتر دانشکدهٔ فیزیک برگزار خواهد شد.
سمینار این هفته را <آقای رازبین> برگزار خواهند کرد. عنوان و چکیدهٔ سمینار ایشان به شرح زیر است:
Title:
general relativistic mass and velocity for LTB structure.
Abstract:
This presenttion is about first steps of my M.sc project under supervision of profesor Reza Mansouri and
it deal with calculation of velocity and mass profile for a LTB structure.this will lead to direct camparition of classical profile
and general relativistic profile.I will disscus about clear diffinition of problem and then I will show some calculation about
angular velocity and I will finish presentation with some quastion
این سمینار در روز <یکشنبه> <4 مهر1389> در ساعت <15:00> در اتاق ۵۱۷ (اتاق قطب علمی) در طبقهٔ پنجم دانشکدهٔ فیزیک برگزار خواهد شد.
کنفرانس In the Spirit of Lyot 2010 در باره رصد مستقیم سیارات فراخورشیدی و دیسک های ستاره ای از 25 الی 29 اکتبر در پاریس برگزار می شود . برای اطلاعات بیشتر به وبگاه این کنفرانس مراجعه کنید.
از این پس سعی خواهیم کرد ، اطلاعات و اعلانات مربوط به کنفرانس های مربوط به کیهانشناسی و اختر فیزیک را در وبگاه گروه قرار دهیم. لطفا در به روزرسانی اعلام کنفرانس ها همراهی کنید .
سمینار این هفته را برگزار خواهند کرد. عنوان و چکیدهٔ سمینار ایشان به شرح زیر است:
Title:
Weak Gravitational Lensing an observation for accelerating universe.
Abstract:
The expansion history of universe is not able to distinguish between DE and MG theories.
Consequently new type of observations related to the issue of structure formation is needed for this task.
Weak gravitational lensing considering the LSS in the universe is such a probe. In this talk we review the basic concepts
of cosmological shear statistics which is related to the matter power spectrum in the Universe and then we will show, how the accelerating models have put their fingerprints on weak
gravitational lensing.
این سمینار در روزیکشنبه 9 اسفند در ساعت 15 در اتاق ۵۱۷ (اتاق قطب علمی) در طبقهٔ پنجم دانشکدهٔ فیزیک برگزار خواهد شد.
سمینار این هفته را برگزار خواهند کرد. عنوان و چکیدهٔ سمینار ایشان به شرح زیر است:
Title:
Weak Gravitational Lensing an observation for accelerating universe.
Abstract:
The expansion history of universe is not able to distinguish between DE and MG theories.
Consequently new type of observations related to the issue of structure formation is needed for this task.
Weak gravitational lensing considering the LSS in the universe is such a probe. In this talk we review the basic concepts
of cosmological shear statistics which is related to the matter power spectrum in the Universe and then we will show, how the accelerating models have put their fingerprints on weak
gravitational lensing.
این سمینار در روزیکشنبه2 اسفند در ساعت 15 در اتاق ۵۱۷ (اتاق قطب علمی) در طبقهٔ پنجم دانشکدهٔ فیزیک برگزار خواهد شد.
