We update the light curve of Type II SN 2009ls. The light curves show that the luminosity have evolved in the rapid decline phase. The timescale until this rapid decline would allow us to estimate the mass of the hydrogen shell.
■ [dwarf nova] Reanalysis of OT J104411.4+211307
We performed the reanalysis of the dwarf nova OT J104411.1+211307 (=CSS100217). The flux distribution in our reanalysis are well similar to that of a typical dwarf nova undergoing an outburst. We can confirm that there is an weak emission in the center of the H alpha absorption.
We started the photometric observations of Type Ic SN 2010X. We adopted the reference magnitude of comparison star from USNO B1.0 catalog for the measuring the magnitude of SN. The preliminary results suggest that the luminosity has begun to be in decline phase. The decline rate of the light curve in the bluer bands show the more faster than those of the redder bands. We continue the observations of Type Ic SN 2010X.
We performed the spectroscopic observations of Type Ia SN 2010Y. Our spectrum shows the absorptions feature are broadened because of the expansion velocity. We confirm that the line profile is resemble of that of a typical SN Ia. The deep SiII absorption at 5800A indicates that SN 2010Y is categorized to slightly intrinsic dim object. This characteristic is corresponding to that the maximum absolute magnitude is derived as -18.1 mag from the our light curve. We cannot confirm the any features of CII 6580, which was seen at a week before maximum (reported in CBET 2168).
■ Optical transient of UGC 2773 : update
We update the light curve of the optical transient of UGC 2773.
■ [Recurrent Nova] U Sco : update
We update the light curve and spectrum of the recurrent nova U Sco.
We have started the observations of the Type Ia SN 2010Y. This SN was discovered in the nearby possible elliptical galaxy NGC 3392 (its distance modulus is 33.3.) on Feb. 8.8 (UT) by Giancarlo Cortini (reported in CBET 2168). The spectroscopic observations were performed by D. Milisavljevic and R. Fesen, reported in CBET 2168. They showed that the spectrum is similar to that of normal Type Ia SN 1994D at an week before maximum. The Carbon signature might be also seen in their spectrum. It indicates that this SN may evolve in the just days after explosions. We show the light curves of SN 2010Y in BVRcIc-band. They show the rapid rising luminosity, which does still not reach the maximum light. We will continue the observations of the Type Ia SN 2010Y.
We update the spectrum of Nova Oph 2010 obtained on Feb. 12. The profiles of emission lines don't almost seem to largely change. We continue the observations of this object.
■ [Recurrent Nova] U Sco : update
We update the photometric and spectroscopic results of the recurrent nova U Sco. The recent spectrum shows that the emission lines of the Balmer series become weak comparing to those of previous phase. The photometry indicate that the this nova evolved in the plateau phase.
We performed the spectroscopic observations of Nova Oph 2010 since Jan. 25. The strong features of Balmer series and NaID show the P-Cyg profile with weak absorptions. The FeII multiplet features are also seen in the regions around 5000-5300A. These characteristics suggest that Nova Oph 2010 is classified into the FeII class in its early phase (Williams 1992). The OI 7774, 8227, 8446 also still form the P-Cyg profile on Feb. 5. The P-Cyg profile dominated spectra continue to form for 10 days. It indicates that the ejecta of Nova Oph 2010 slowly evolved and expanded. An emission of the H alpha strongly develops with time. We will continue the spectroscopic monitoring the Nova 2010 Oph.
■ [Recurrent Nova] U Sco : update
We performed the photometric and spectroscopic observations of the recurrent nova U Sco. The light curve show that this object evolved in the plateau phase. The radiations emitted in this stage are composed to the black body temperature from the optically thick wind and the free-free emissions from the irradiations of the accretion disk on the central white dwarf. The spectrum obtained on Feb. 5 shows that an weak emission line appears at 5400A and the emissions of the HeI 5876 and 7065 simultaneously begin to weaken. The weak emissions line at 5400A is thought to be HeII, which had already been identified in the spectra obtained 6 days after the 1987 outburst (Sekiguchi et al. 1988). Such an appearance of the higher excited level line indicate that the optically thick photosphere would recede enough. We will be able to the research the higher temperature regions in the inner shell comparing to that at the previous phase.
■ [Recurrent Nova] Optical and Near-infrared Observations of U Sco : update
We have performed the optical and near-infrared observations of a recurrent nova U Sco since Jan. 28 UT. The photometric observations in optical and near-inrfared wavelength regions indicate that the luminosity show a rapid decline rate as confirmed in early phase for a very fast novae. The rapid decline of the near-infrared regions suggests that formations of a dust in the ejected material in the novae atmosphere would not occur little. Spectroscopic observations indicate that a dramatical change is confirmed in the profile in the emissions line. For example, the peak of the Balmer series show the development of the relative strength of the central component with time. The three components of the emissions line of the Balmer had been also confirmed in the spectra of the outburst in 1999. We continue the observations of the recurrent nova U Sco.
■ Optical transient in UGC 2773 : update
We update the light curve of the optical transient of UGC 2773. Recently, the light curve shows the brightening of ~ 0.5 mag in V, R, I-bands. We confirmed that the brightness of V, R, and I band simultaneously increase so that it has not been seen with last brightening.
3C 454.3 has been an outburst with the rising in the gamma-ray region. Recently, the outburst seems to have finished and to be a faint state.
■ [Recurrent Nova] U Sco spectra
We update the spectra of U Sco which was obtained Feb. 2.79. We confirmed that the spectrum clearly shows stronger emissions line of Balmer series than those obtained on the outburst date. The velocity of these emissions decreased comparing to those of previous phase. The possible Nitrogen lines became strong compared to those of previous phase. On the other hand, the strength of O I emissions line weakened. The redshifted emissions line of HeI show the decline of the velocity due to Doppler effect and narrower width than those of Jan. 28. The decline of the velocity of Hydrogen and Helium indicates that the ejected shell expands with time and we could search the physical state of the material distributed in the inner parts.