ATLAS photometry of 1308+326 shows continued brightening
ATel #15480; E. K. Urbach and C. W. Stubbs (Harvard University), L. Denneau, J. Tonry, A. Lawrence. R. Siverd, H. Weiland (IfA, University of Hawaii), K. W. Smith, D. R. Young, S. J. Smartt, (Queenâs University Belfast), L. Shingles (GSI/QUB) N. Erasmus, W. Koorts (South African Astronomical Observatory), J. Anderson (ESO), A. Clocchiatti (PUC), F. Forster (CMM), G. Pignata (MAS), A. Rest (STScI)
on 28 Jun 2022; 19:19 UT
Credential Certification: Elana Urbach (eurbach@g.harvard.edu)
Subjects: Optical, AGN, Blazar
Multiple reports show an outburst of 1308+326 as recently reaching a record optical brightness (see ATel #15476, ATel #15474, ATel #15459, ATel #15447). Here we present the recent light curve of this object from the ATLAS survey's public photometry server[1]. ATLAS images the sky ~nightly in the custom visible c (420-650 nm) and o (560-820 nm) bands[2], and has imaged 1308+326 over more than 5 years. Data are made immediately available and can be accessed at the link provided below, for both regular and frame-subtraction photometry[1].
We compare the magnitude of 1308+326 to reference star C from Smith et al[3], and present evidence of the increase in brightness consistent with previous observations. Comparison star C has mean c-band and o-band AB magnitudes of C_c=13.96 and C_o=13.58, respectively.
Tables 1 and 2 present delta-c = c-mag(1380+326) minus C_c and o-mag(1380+326) minus C_o. Prior and subsequent data can be obtained from the ATLAS photometry server[1]. Typical photometric uncertainties per measurement are 0.07 mag. The source continues to increase in brightness.
Table 1: c-band magnitude differences 1380+326 minus star C.
| MJD | delta-c |
| 59750.2770 | 0.986 |
| 59750.2989 | 1.042 |
| 59750.3025 | 0.974 |
| 59750.3188 | 0.999 |
| 59753.3208 | 0.24 |
| 59753.3263 | 0.265 |
| 59753.3304 | 0.267 |
| 59753.3442 | 0.227 |
| 59754.3227 | -0.167 |
| 59754.3328 | -0.341 |
| 59754.3383 | 0.107 |
| 59754.3397 | 0.091 |
| 59754.3415 | 0.123 |
| 59754.3429 | 0.122 |
| 59754.3484 | 0.116 |
| 59754.3585 | 0.078 |
| 59757.3376 | -0.485 |
| 59757.3412 | -0.600 |
| 59757.3526 | -0.172 |
| 59757.3590 | -0.225 |
| 59757.3594 | -0.179 |
| 59757.3695 | -0.183 |
Table 2: o-band magnitude differences 1380+326 minus star C.
| MJD | delta-o |
| 59751.2833 | 0.756 |
| 59751.2888 | 0.696 |
| 59751.3054 | 0.728 |
| 59751.3211 | 0.724 |
| 59752.3156 | 0.655 |
| 59752.3188 | 0.623 |
| 59752.3257 | 0.65 |
| 59752.3377 | 0.645 |
| 59755.3448 | 0.03 |
| 59755.3480 | 0.036 |
| 59755.3535 | -0.023 |
| 59755.3711 | 0.009 |
| 59756.3240 | -0.106 |
| 59756.3277 | -0.108 |
| 59756.3341 | -0.097 |
| 59756.3480 | -0.089 |
[1] Shingles L. et al. Astronote 2021-7, https://fallingstar-data.com/forcedphot/.
[2] Tonry J. et al. 2018, PASP, 130:064505.
[3] Smith et al. 1985, AJ, 90, 1184.
The Asteroid Terrestrial-impact Last Alert System (ATLAS) project is primarily funded to search for Near-Earth asteroids through NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575; byproducts of the NEO search include images and catalogs from the survey area. This work was partially funded by Kepler/K2 grant J1944/80NSSC19K0112 and HST GO-15889, and STFC grants ST/T000198/1 and ST/S006109/1. The ATLAS science products have been made possible through the contributions of the University of Hawaii Institute for Astronomy, the Queen's University Belfast, the Space Telescope Science Institute, the South African Astronomical Observatory, and The Millennium Institute of Astrophysics (MAS), Chile.
ATLAS Public Photometry Server
