High-time-resolution observations of supernovae with Aqueye+: ASASSN-14kg, PSN J07285597+5611462, PSN J09204691-0803340
ATel #6875; L. Zampieri (INAF-Astronomical Observatory of Padova), E. Verroi (University of Padova), M. Barbieri (Universidad de Atacama, INAF-Astronomical Observatory of Padova), G. Naletto (University of Padova), C. Barbieri (University of Padova)
on 5 Jan 2015; 12:20 UT
Credential Certification: Luca Zampieri (luca.zampieri@oapd.inaf.it)
Subjects: Optical, Supernovae
Referred to by ATel #: 7351
As part of a pilot program for the search of optical timing signals in recent supernovae, we observed the following objects with the fast photon counter Aqueye+ mounted at the 182 cm Copernico telescope in Asiago Cima Ekar (for a short description of the instrument, see Naletto et al. 2013, Proc. SPIE 8875, Quantum Communications and Quantum Imaging XI, 88750D):
| Object | RA (J2000) | DEC (J2000) | |
| ASASSN-14kg | 01:44:38.38 | +35:48:20.5 | (ATel #6714, #6721; Type II) |
| PSN J07285597+5611462 | 07:28:55.97 | +56:11:46.2 | (CBAT TOCP, ATel #6723; Type IIn) |
| PSN J09204691-0803340 | 09:20:46.91 | -08:03:34.0 | (CBAT TOCP, ATel #6734; Type IIn) |
The selected targets are recent and bright (V<17) core collapse supernovae (ASASSN-14k was reported to us by the Padova-Asiago Supernova Group). Data were collected in white light during the nights of 20-23 November 2014, as shown in the following table (mean count rate and root mean square [rms] variation refer to the sum of all 4 on-source channels; numbers in parentheses are background subtracted; values are not corrected for atmospheric extinction and seeing):
| Object | Date | Start time | Stop time | Duration | Mean count rate | rms |
| | (UTC) | (UTC) | (s) | (1/s) | (1/s) |
| ASASSN-14kg | 2014 11 20 | 19:58:26 | 20:58:26 | 3600 | 5643 (2739) | 263 |
| ASASSN-14kg | 2014 11 21 | 20:26:46 | 21:26:44 | 3598 | 5760 (3146) | 305 |
| PSN J07285597+5611462 | 2014 11 22 | 04:42:20 | 05:12:20 | 1799 | 8582 (4701) | 754 |
| PSN J09204691-0803340 | 2014 11 23 | 04:03:57 | 04:33:56 | 1798 | 4629 (761) | 117 |
We binned the photon event lists of the 4 summed on-source channels and computed light curves and power density spectra with different time bins. No optical pulsations were detected in the non-averaged power spectra. Adopting a 0.5 ms time bin, the upper limit to the fractional rms variation of the signal power in the frequency range 0.5-1000 Hz is (90% confidence level):
| Object | Date | Frequency resolution | Fractional rms of signal power |
| | (mHz) | |
| ASASSN-14kg | 2014 11 20 | 0.28 | <0.0013 |
| ASASSN-14kg | 2014 11 21 | 0.28 | <0.0013 |
| PSN J07285597+5611462 | 2014 11 22 | 0.56 | <0.0016 |
| PSN J09204691-0803340 | 2014 11 23 | 0.56 | <0.0020 |
