RA/DEC (2000)
21:16:01.364 -58:38:03.67
319.005684 -58.6343533333
Type
SN II
Redshift
0.0345
Discovery ReportClassification Report
Related AstroNotes: 2025-289
Reporting Group
ATLAS
Discovering Data Source
ATLAS
Discovery Date
2025-09-16 02:56:05.856
TNS AT
Y
Public
Y
Discovery Mag
19.215
Filter
cyan-ATLAS
Reporter/s
J. Tonry, L. Denneau, H. Weiland, R. Siverd (IfA, University of Hawaii), N. Erasmus, W. Koorts (South African Astronomical Observatory), A. Jordan, V. Suc (UAI, Obstech), M. R. Alarcón, J. Licandro, P. Nichita (IAC), S. J. Smartt, K. W. Smith (Oxford/QUB), D. R. Young, M. Nicholl, M. Fulton, M. McCollum, T. Moore, J. Weston, X. Sheng, C. R. Angus, A. Wilson, A. Aamer, D. Magill, P. J. Broda (QUB), P. Ramsden (Birmingham/QUB), L. Shingles (GSI/QUB), S. Srivastav, J. H. Gillanders, H. Stevance, A. J. Cooper, F. Stoppa, J. Tweddle (Oxford), L. Rhodes (TSI/McGill), A. Rest (STScI), T.-W. Chen (NCU), C. Stubbs (Harvard), J. S. Sommer (LMU), B. P. Schmidt (ANU)
NEDSIMBADDECaLSPanSTARRS-1SkyMapperVizieRWISEDSSADS

Spectra

 ▌SN_2025xxi - 2025-09-22 02:41:29 VLT-UT1 / FORS2 (adH0cc)z=
▌Show H at z=vexp= km/s
▌Show He at z=vexp= km/s
▌Show He II at z=vexp= km/s
▌Show C II at z=vexp= km/s
▌Show C III at z=vexp= km/s
▌Show C IV at z=vexp= km/s
▌Show N II at z=vexp= km/s
▌Show N III at z=vexp= km/s
▌Show N IV at z=vexp= km/s
▌Show N V at z=vexp= km/s
▌Show O at z=vexp= km/s
▌Show [O I] at z=vexp= km/s
▌Show O II at z=vexp= km/s
▌Show [O II] at z=vexp= km/s
▌Show [O III] at z=vexp= km/s
▌Show O V at z=vexp= km/s
▌Show O VI at z=vexp= km/s
▌Show Na at z=vexp= km/s
▌Show Mg at z=vexp= km/s
▌Show Mg II at z=vexp= km/s
▌Show Si II at z=vexp= km/s
▌Show S II at z=vexp= km/s
▌Show Ca II at z=vexp= km/s
▌Show [Ca II] at z=vexp= km/s
▌Show Fe II at z=vexp= km/s
▌Show Fe III at z=vexp= km/s
▌Show Å at z=vexp= km/s
▌Show Å at z=vexp= km/s
▌Show Å at z=vexp= km/s
▌Show Å at z=vexp= km/s
▌Show Tellurics 
▌Show Galaxy lines at z=
▌Show WR-WN at z=vexp= km/s
▌Show WR-WC/O at z=vexp= km/s
   Binning factor: (rounded to nearest integer >1)
Mouse hovers at WL: 0 (rest),0 (observed)

Light curves

 ▌GOTO-S_GOTO-4_L
 ▌ATLAS-CHL_ATLAS-04_cyan
 ▌ATLAS-STH_ATLAS-03_orange
   
Pointer position (MJD, Mag, Abs.Mag): (0.00, 0.00, 0.00)
Spectra
 ID Obs-date (UT) Tel / Inst Exp-Time Observer/s Reducer/s Group Spectrum ascii file Spectrum fits file Spec. Type Assoc. Groups End prop. period Remarks
22069 2025-09-22 02:41:29 VLT-UT1 / FORS2 900 service G. Csoernyei adH0cc tns_2025xxi_2025-09-22_02-41-29_VLT-UT1_FORS2_adH0cc.asci tns_2025xxi_2025-09-22_02-41-29_VLT-UT1_FORS2_adH0cc.fits Object Quick-reduction spectrum
Light Curves
Filter Tel / Inst Obs-date range JD Range Photometry
L-GOTO GOTO-S_GOTO-4 2025-09-02 13:16:51 - 2025-09-23 13:38:38 2460921.053374 - 2460942.068504 2
Photometry
ID Obs-date JD Mag. / Flux Err Lim. Mag./Flux Units Filter Tel / Inst Exp-time Observer/s Remarks
519563 2025-09-23 13:38:38 2460942.068504 18.74 0.08 ABMag L-GOTO GOTO-S_GOTO-4 180
519562 2025-09-02 13:16:51 2460921.053374 19.4 ABMag L-GOTO GOTO-S_GOTO-4 180 [Last non detection]
cyan-ATLAS ATLAS-CHL_ATLAS-04 2025-09-16 02:56:06 - 2025-09-16 02:56:06 2460934.62229 - 2460934.62229 1
Photometry
ID Obs-date JD Mag. / Flux Err Lim. Mag./Flux Units Filter Tel / Inst Exp-time Observer/s Remarks
518336 2025-09-16 02:56:06 2460934.62229 19.215 0.196 19.4 ABMag cyan-ATLAS ATLAS-CHL_ATLAS-04 30 Robot
orange-ATLAS ATLAS-STH_ATLAS-03 2025-09-14 21:25:43 - 2025-09-14 21:25:43 2460933.39286 - 2460933.39286 1
Photometry
ID Obs-date JD Mag. / Flux Err Lim. Mag./Flux Units Filter Tel / Inst Exp-time Observer/s Remarks
518335 2025-09-14 21:25:43 2460933.39286 19.61 ABMag orange-ATLAS ATLAS-STH_ATLAS-03 30 Robot [Last non detection]
AT Reports
ID Time received (UT) Sender Reporter/s Reporting group Disc. Data Source RA DEC Discovery date (UT) Discovery Mag. Filter Related files AT Type Host name Internal name Assoc. Groups End prop. period Remarks ADS Bibcode Unreal Auto classification
271148 2025-09-24 08:53:45 GOTO_bot D. O'Neill,K. Ackley,M. Dyer et al. GOTO GOTO 21:16:01.390 -58:38:04.33 2025-09-23 13:38:38.400 18.74 L-GOTO Other GOTO25hnk GOTO N
270574 2025-09-18 13:12:03 ATLAS_Bot1 J. Tonry,L. Denneau,H. Weiland et al. ATLAS ATLAS 21:16:01.364 -58:38:03.67 2025-09-16 02:56:05.856 19.215 cyan-ATLAS PSN ATLAS25lon ATLAS 2025TNSTR3753....1T N
Classification Reports
ID Time received (UT) Sender Classifier/s Group Classification Redshift Spectra Related files Assoc. Groups End prop. period Remarks ADS Bibcode
22069 2025-09-22 11:27:00 Geza Csornyei G. Csoernyei, B. Leibundgut, J. Spyromilio, S. Blondin (ESO), S. Taubenberger (TUM / MPA), W. Hillebrandt (MPA) adH0cc SN II 0.0345 1 adH0cc The spectrum shows P Cygni features of H and He, indicative of a young Type II supernova. 2025TNSCR3812....1C
Spectra
ID Obs-date (UT) Tel / Inst Exp-Time Observer/s Reducer/s Group Spectrum ascii file Spectrum fits file Spec. Type Assoc. Groups End prop. period Remarks
22069 2025-09-22 02:41:29 VLT-UT1 / FORS2 900 service G. Csoernyei adH0cc tns_2025xxi_2025-09-22_02-41-29_VLT-UT1_FORS2_adH0cc.asci tns_2025xxi_2025-09-22_02-41-29_VLT-UT1_FORS2_adH0cc.fits Object Quick-reduction spectrum

Comments