J/MNRAS/449/1941 Optical/NIR photometry of OGLE-2012-SN-006 (Pastorello+, 2015) ================================================================================ Massive stars exploding in a He-rich circumstellar medium - V. Observations of the slow-evolving SN Ibn OGLE-2012-SN-006. Pastorello A., Wyrzykowski L., Valenti S., Prieto J.L., Kozlowski S., Udalski A., Elias-Rosa N., Morales-Garoffolo A., Anderson J.P., Benetti S., Bersten M., Botticella M.T., Cappellaro E., Fasano G., Fraser M., Gal-Yam A., Gillone M., Graham M.L., Greiner J., Hachinger S., Howell D.A., Inserra C., Parrent J., Rau A., Schulze S., Smartt S.J., Smith K.W., Turatto M., Yaron O., Young D.R., Kubiak M., Szymanski M.K., Pietrzynski G., Soszynski I., Ulaczyk K., Poleski R., Pietrukowicz P., Skowron J., Mroz P. =2015MNRAS.449.1941P (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: Supernovae ; Photometry, UBVRI ; Photometry, infrared Keywords: supernovae: general - supernovae: individual: OGLE-2012-SN-006 - supernovae: individual: SN 2006jc - supernovae: individual: SN 2010al Abstract: We present optical observations of the peculiar Type Ibn supernova (SN Ibn) OGLE-2012-SN-006, discovered and monitored by the Optical Gravitational Lensing Experiment-IV survey, and spectroscopically followed by Public ESO Spectroscopic Survey of Transient Objects (PESSTO) at late phases. Stringent pre-discovery limits constrain the explosion epoch with fair precision to JD=2456203.8+/-4.0. The rise time to the I-band light-curve maximum is about two weeks. The object reaches the peak absolute magnitude M_I_=-19.65+/-0.19 on JD=2456218.1+/-1.8. After maximum, the light curve declines for about 25 d with a rate of 4 mag (100 d)^-1^. The symmetric I-band peak resembles that of canonical Type Ib/c supernovae (SNe), whereas SNe Ibn usually exhibit asymmetric and narrower early-time light curves. Since 25 d past maximum, the light curve flattens with a decline rate slower than that of the ^56^Co-^56^Fe decay, although at very late phases it steepens to approach that rate. However, other observables suggest that the match with the ^56^Co decay rate is a mere coincidence, and the radioactive decay is not the main mechanism powering the light curve of OGLE-2012-SN-006. An early-time spectrum is dominated by a blue continuum, with only a marginal evidence for the presence of HeI lines marking this SN type. This spectrum shows broad absorptions bluewards than 5000 {AA}, likely OII lines, which are similar to spectral features observed in superluminous SNe at early epochs. The object has been spectroscopically monitored by PESSTO from 90 to 180 d after peak, and these spectra show the typical features observed in a number of SN 2006jc-like events, including a blue spectral energy distribution and prominent and narrow ({nu}_FWHM_~1900 km/s) HeI emission lines. This suggests that the ejecta are interacting with He-rich circumstellar material. The detection of broad (10^4^ km/s) OI and CaII features likely produced in the SN ejecta (including the [OI] {lambda}{lambda}6300,6364 doublet in the latest spectra) lends support to the interpretation of OGLE-2012-SN-006 as a core-collapse event. Description: Photometric measurements in the optical and NIR bands were obtained through the PSF-fitting technique. A template PSF was built using stars in the SN field. With this PSF model along with a low-order polynomial surface, we finally performed a fit to the SN and the underlying background. OGLE-IV photometry was obtained using the difference imaging analysis, which is a template subtraction method adapted to the OGLE data and detailed in Wyrzykowski et al. 2014, J/AcA/64/197 (see also Wozniak 2000, J/AcA/50/421). Objects: --------------------------------------------------------------- RA (ICRS) DE Designation(s) --------------------------------------------------------------- 03 33 34.79 -74 23 40.1 OGLE-2012-SN-006 = OGLE 2012-SN-6 --------------------------------------------------------------- File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file tablea1.dat 77 123 Optical photometry of OGLE-2012-SN-006 tablea2.dat 54 7 NIR photometry of OGLE-2012-SN-006 -------------------------------------------------------------------------------- See also: J/AcA/50/421 : OGLE-II DIA BUL_SC1 field (Wozniak, 2000) J/AcA/64/197 : OGLE-IV 2012-2014 transients (Wyrzykowski+, 2014) J/A+A/602/A93 : SN Type Ibn OGLE-2014-SN-131 lightcurves (Karamehmetoglu+, 2017) Byte-by-byte Description of file: tablea1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 10 A10 "date" Date Observation date 12- 19 F8.2 d JD Julian Date (JD-2400000) 21- 25 F5.2 mag Umag ? U-band magnitude 27- 30 F4.2 mag e_Umag ? Uncertainty in Umag 32- 36 F5.2 mag Bmag ? B-band magnitude 38- 41 F4.2 mag e_Bmag ? Uncertainty in Bmag 43- 47 F5.2 mag Vmag ? V-band magnitude 49- 52 F4.2 mag e_Vmag ? Uncertainty in Vmag 54- 58 F5.2 mag Rmag ? R-band magnitude 60- 63 F4.2 mag e_Rmag ? Uncertainty in Rmag 65 A1 --- l_Imag [>] Limit flag on Imag 66- 70 F5.2 mag Imag ? I-band magnitude 72- 75 F4.2 mag e_Imag ? Uncertainty in Imag 77 I1 --- Inst [1/6] Instrument identification (G1) -------------------------------------------------------------------------------- Byte-by-byte Description of file: tablea2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 10 A10 "date" Date Observation date 12- 19 F8.2 d JD Julian Date (JD-2400000) 21- 25 F5.2 mag Jmag J-band magnitude 27- 30 F4.2 mag e_Jmag Uncertainty in Jmag 32- 36 F5.2 mag Hmag ? H-band magnitude 38- 41 F4.2 mag e_Hmag ? Uncertainty in Hmag 43- 47 F5.2 mag Kmag ? K-band magnitude 49- 52 F4.2 mag e_Kmag ? Uncertainty in Kmag 54 I1 --- Inst [1/6] Instrument identification (G1) -------------------------------------------------------------------------------- Global notes: Note (G1): Instrument as follows: 1 = 1.3-m Warsaw University Telescope + OGLE-IV mosaic camera (Las Campanas Observatory); 2 = 2.2-m MPI/ESO Telescope + GROND (ESO-La Silla Observatory); 3 = 3.58-m New Technology Telescope + EFOSC2 (ESO-LaSilla Observatory); 4 = LCOGT 1.0m-05 telescope + SBIG STX-16083 with Kodak KAF-16803 FI (Cerro Tololo InterAmerican Observatory); 5 = LCOGT 1.0m-09 telescope + SBIG STX-16083 with Kodak KAF-16803 FI (Cerro Tololo Inter-American Observatory); 6 = 3.58-m New Technology Telescope + SOFI (ESO-La Silla Observatory). -------------------------------------------------------------------------------- History: From electronic version of the journal References: Pastorello et al. Paper I. 2008MNRAS.389..113P Pastorello et al. Paper II. 2008MNRAS.389..131P Mattila et al. Paper III. 2008MNRAS.389..141M Pastorello et al. Paper IV. 2015MNRAS.449.1921P, Cat. J/MNRAS/449/1921 Pastorello et al. Paper VI. 2015MNRAS.449.1954P Pastorello et al. Paper VII. 2015MNRAS.453.3649P Pastorello et al. Paper VIII. 2015MNRAS.454.4293P Pastorello et al. Paper IX. 2016MNRAS.456..853P ================================================================================ (End) Tiphaine Pouvreau [CDS] 06-Dec-2017