ВНИМАНИЕ! На форуме начался конкурс - астрофотография месяца ИЮЛЬ-АВГУСТ!
0 Пользователей и 1 Гость просматривают эту тему.
Удивило, что разбег значений около одной звездной величины. Это 22-го в первой половине суток. Это в космосе! Ни облачность не мешает, ни комары. Или это звезда так быстро изменяется?
Цитата: wladimir от 01 Мая 2012 [08:54:10]Удивило, что разбег значений около одной звездной величины. Это 22-го в первой половине суток. Это в космосе! Ни облачность не мешает, ни комары. Или это звезда так быстро изменяется? Скорее всего, точность одного измерения в реальности не выше 0.5m.. Что у любителей, что у профи. Наслушался я тут сказок про фитцы и жопег, а в реальности - точность достигается числом и усреднением
Кривая блеска Новой Стрельца 2012 года с потрясающей детализацией получена космическим аппаратом STEREO. Он застал фазу подъема вспышки около 20h-21h UT 20 апреля - за несколько часов до снимков Стаса, на которых Новая была открыта.Кривая STEREO уникальна тем, что снята одним и тем же прибором в одном диапазоне и без суточных интервалов в наблюдениях, которые неизбежны для наземных обсерваторий.
Radio, X-ray and UV observations of Nova Sgr 2012ATel #4088; Thomas Nelson (Minnesota), Koji Mukai (UMBC and NASA/GSFC), Jennifer Sokoloski (Columbia), Laura Chomiuk (NRAO and CfA), Michael Rupen (NRAO) and Amy Mioduszewski (NRAO)on 3 May 2012; 19:17 UTSubjects: Radio, Ultra-Violet, X-ray, NovaNova Sgr 2012 (PNV J17452791-2305213) was discovered on 2012 Apr 21 (CBET 3089). The optical evolution during the first 5 days was captured in great detail by the STEREO mission, revealing a very fast decay from maximum brightness (see http://stereo.gsfc.nasa.gov ). Early spectroscopy indicated high velocity ejecta in this nova, with an H alpha line FWHM of 5600 km/s (CBET 3089). Sokolovsky et al. observed Nova Sgr with Swift one day after discovery, and reported a non-detection in X-rays (ATel #4061).We observed Nova Sgr 2012 with the Jansky Very Large Array at Ka band (32 GHz) on 2012 April 23.5, 3 days after initial discovery. Our observation resulted in a non-detection of 32 +/- 25 microJy at the position of the nova.We also observed the nova with Swift/XRT for 5955 s between 2012 April 25.7 and 2012 April 26.1, approximately 6 days after the initial discovery. No X-ray source was detected at the position of the nova, with a 90% confidence upper limit to the 0.3-10 keV count rate of 1.3e-3 c/s. Assuming 5 keV thermal bremsstrahlung emission attenuated by an absorbing column density of 1e22 cm^-2, this count rate limit corresponds to a 0.3-10 keV flux limit of 7.8e-14 erg/s/cm^-2.The UVOT instrument also obtained images of Nova Sgr 2012 in the UVM2 band on 2012 Apr 25.7, with a total exposure time of 5975 s. The nova is clearly detected, with an average UVM2 brightness of 13.71 +/- 0.09 mag. Over the course of our observation, the UVM2 magnitude faded from 13.5 to 13.8.These observations were obtained as part of the E-Nova project (formerly the EVLA Nova Project, see link below), an effort to obtain high quality radio light curves and complimentary multiwavelength observations of novae visible to the Jansky Very Large Array. Further radio and X-ray observations of this nova are planned.E-Nova Project
INFRARED OBSERVATIONS OF NOVA SAGITTARII 2012 = PNV J17452791-2305213ATel #4093; N. M.Ashok Physical Research Laboratory, Ahmedabad 380009, Indiaon 5 May 2012; 05:06 UTSubjects: Infra-Red, Cataclysmic Variable, NovaINFRARED OBSERVATIONS OF NOVA SAGITTARII 2012 = PNV J17452791-2305213 Ashish Raj, N. M. Ashok, D. P. K. Banerjee and V. Venkata Raman, Physical Research Laboratory, report near-infrared J-, H-, and K-band photometry of the Nova Sgr 2012 (cf. CBET 3089) obtained with the Mt. Abu 1.2-m telescope (+PRL Near-Infrared NICMOS3 Imager/Spectrometer). The preliminary reduction of these Mt. Abu observations of 2012 April 29.978 UT and May 1.896 UT shows the declining trend in the brightness of the nova in the JHK bands. The JHK magnitudes for April 29.978 are 9.15, 9.01, 8.17 and May 1.896 are 9.65, 9.45, 8.57 with the typical errors estimated to be +/- 0.04 mag respectively from the photometry.
Spectroscopy of the Nova Sagitarii 2012 (PNV J17452791-2305213)ATel #4094; V. F. Esipov (SAI MSU), K. V. Sokolovsky (ASC Lebedev/SAI MSU), and S. A. Korotkiy (Ka-Dar Obs.)on 5 May 2012; 07:36 UTSubjects: Optical, NovaNova Sagitarii 2012 (CBET #3089; ATel #4061, #4088, #4093) was observed spectroscopically with the 1.25m ZTE telescope of the Crimean Laboratory, Moscow State University. Three intermediate resolution spectra (R=2000) covering the range 4000-9000A were obtained on April 24.04, 26.01, and 27.03 UT (3, 5 and 6 days after the explosion). All spectra are dominated by broad H_alpha, H_beta and OI emission corresponding to expansion velocities up to 6500km/s. The estimated expansion velocities are slightly larger than those reported on April 23 and 25 by C. Buil and K. Imamura (CBET #3089). The presence of H_gamma and HeII 4686 lines is evident in the April 26 spectrum.Detection of HeII emission together with the flat-top shape of emission lines, high expansion velocity and rapid lightcurve evolution allows one to classify the object as a fast He/N type nova (Williams 1992, AJ, 104, 725).
2012-01-022012-01-032012-01-042012-01-062012-01-102012-01-132012-01-182012-01-202012-01-212012-01-242012-01-252012-01-262012-01-272012-01-282012-01-292012-01-302012-01-312012-02-012012-02-022012-02-032012-02-042012-02-052012-02-062012-02-072012-02-092012-02-102012-02-112012-02-252012-02-262012-02-272012-03-032012-03-042012-03-052012-03-062012-03-072012-03-092012-03-102012-03-112012-03-132012-03-152012-03-162012-03-172012-03-182012-03-192012-03-212012-03-232012-03-252012-03-272012-03-292012-03-312012-04-022012-04-032012-04-042012-04-052012-04-062012-04-072012-04-082012-04-092012-04-122012-04-132012-04-142012-04-172012-04-202012-04-212012-04-222012-04-232012-04-242012-04-25
Detection of hard X-ray emission from Nova Sgr 2012 with SwiftATel #4110; Thomas Nelson (Minnesota), Koji Mukai (UMBC and NASA/GSFC), Jennifer Sokoloski (Columbia), Laura Chomiuk (NRAO and CfA), Michael Rupen (NRAO) and Amy Mioduszewski (NRAO)on 11 May 2012; 19:14 UTSubjects: Ultra-Violet, X-ray, NovaWe observed Nova Sgr 2012 (PNV J17452791-2305213) with the Swift satellite on 2012 May 10, 40 days after the discovery of this nova. The total exposure time with the XRT instrument was 6280 s. In contrast to the non-detections reported in ATels #4061 and #4088, Swift/XRT clearly detected X-ray emission from the nova on 2012 May 10.A total of 249 source counts were detected within a circular region with a radius of 20 pixels centered on the position of the nova, resulting in a 0.3-10 keV count rate of 0.039 c/s. The source spectrum was quite hard, with emission detected at energies up to 10 keV. Modeling the spectrum as an absorbed thermal plasma with the APEC model in XSpec, we find a best fit N(H) of (3 +/- 1) x 10^21 cm^-2, and a lower limit to the plasma temperature of 2.7 x 10^8 K (kT > 23 keV). The 0.3-10 keV flux is 2.7e-12 erg/s/cm^2.The UVOT instrument obtained images in the UVM2 band, with a total exposure time of 6213 s. Nova Sgr 2012 was detected with an average UVM2 magnitude of 16.0 +/- 0.2.These observations were obtained as part of the E-Nova project (formerly the EVLA Nova Project, see link below), an effort to obtain high quality radio light curves and complimentary multiwavelength observations of novae visible to the Jansky Very Large Array.E-Nova Project