RA/DEC (2000)
15:51:54.201 +30:54:08.67
237.97583781 +30.9024079686
Type
SN II
Redshift
0.0848
Reporting Group
ZTF
Discovering Data Source
ZTF
Discovery Date
2025-08-18 04:31:15.003
TNS AT
Y
Public
Y
Discovery Mag
20.9911
Filter
g-ZTF
Reporter/s
Robert Stein (UMD) on behalf of ZTF

Spectra

 SN_2025ulz - 2025-08-24 00:03:40 VLT-UT4 / MUSE (ENGRAVE)z=
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   Binning factor: (rounded to nearest integer >1)
Mouse hovers at WL: 0 (rest),0 (observed)

Light curves

 P48_ZTF-Cam_r
 P48_ZTF-Cam_g
 PS1_GPC1_r
   
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
21859 2025-08-24 00:03:40 VLT-UT4 / MUSE 2800 Camila de Sa Freitas (ESO), Israel Blanchard (ESO), Sam Kim (ESO) Luca Izzo (INAF/OACn) ENGRAVE tns_2025ulz_2025-08-24_00-03-40_VLT-UT4_MUSE_ENGRAVE.txt Object
Light Curves
Filter Tel / Inst Obs-date range JD Range Photometry
r-ZTF P48_ZTF-Cam 2025-08-17 05:11:57 - 2025-08-18 05:50:10 2460904.7166319 - 2460905.7431713 2
Photometry
ID Obs-date JD Mag. / Flux Err Lim. Mag./Flux Units Filter Tel / Inst Exp-time Observer/s Remarks
510132 2025-08-18 05:50:10 2460905.7431713 21.2939 0.125305 ABMag r-ZTF P48_ZTF-Cam
510130 2025-08-17 05:11:57 2460904.7166319 21.0118 ABMag r-ZTF P48_ZTF-Cam [Last non detection]
g-ZTF P48_ZTF-Cam 2025-08-18 04:31:15 - 2025-08-18 04:31:15 2460905.6883681 - 2460905.6883681 1
Photometry
ID Obs-date JD Mag. / Flux Err Lim. Mag./Flux Units Filter Tel / Inst Exp-time Observer/s Remarks
510131 2025-08-18 04:31:15 2460905.6883681 20.9911 0.126861 ABMag g-ZTF P48_ZTF-Cam
r-P1 PS1_GPC1 2025-08-20 07:32:21 - 2025-08-20 07:32:21 2460907.81413 - 2460907.81413 1
Photometry
ID Obs-date JD Mag. / Flux Err Lim. Mag./Flux Units Filter Tel / Inst Exp-time Observer/s Remarks
512490 2025-08-20 07:32:21 2460907.81413 22.05 0.2 20.6 ABMag r-P1 PS1_GPC1 900 Robot
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
267746 2025-08-26 12:29:37 PS1_Bot1 K. C. Chambers, T. de Boer, J. Fairlamb et al. Pan-STARRS Pan-STARRS 15:51:54.201 +30:54:08.67 2025-08-20 07:32:20.832 22.05 r-P1 PSN PS25grr Pan-STARRS N
266521 2025-08-18 14:30:20 ZTF_MMA_bot Robert Stein (UMD) on behalf of ZTF ZTF ZTF 15:51:54.196 +30:54:08.55 2025-08-18 04:31:15.003 20.9911 g-ZTF PSN ZTF25abjmnps ZTF 2025TNSTR3264....1S N
Classification Reports
ID Time received (UT) Sender Classifier/s Group Classification Redshift Spectra Related files Assoc. Groups End prop. period Remarks ADS Bibcode
21859 2025-08-25 08:14:54 Daniele Malesani Smaranika Banerjee (Stockholm University), Maria-Teresa Botticella (INAF - Capodimonte Obs.), Seán J. Brennan (MPE), Enrico Cappellaro (Padua Obs.), Ting-Wan Chen (NCU Taiwan), Paolo D'Avanzo (INAF - Brera Obs.), Valerio D’Elia (ASI-SSDC), Massimiliano De Pasquale (Univ. Messina), Rob A. J. Eyles-Ferris (Leicester), Morgan Fraser (UCD), James H. Gillanders (Oxford), Ben Gompertz (Birmingham), Nusrin Habeeb (Leicester), Luca Izzo (INAF/OAC and DARK/NBI), Peter G. Jonker (Radboud), Andrew J. Levan (Radboud and Warwick), Daniele Bjørn Malesani (DAWN/NBI and Radboud), Antonio Martin-Carrillo (UCD), Matt Nicholl (QUB), Sam Oates (Lancaster U.), Silvia Piranomonte (INAF-OAR), Luigi Piro (INAF-IAPS), Andrea Rossi (INAF - Bologna), Om Sharan Salafia (INAF - Brera Obs.), Nikhil Sarin (Cambridge), Steve Schulze (Northwestern), Avinash Singh (Stockholm University), Stephen J. Smartt (Oxford), Albert Sneppen (DAWN/NBI), Jesper Sollerman (Stockholm), Danny Steeghs (Warwick), Nial R. Tanvir (Leicester), Aishwarya L. Thakur (INAF-IAPS) on behalf of ENGRAVE ENGRAVE SN II 0.0848 1 ENGRAVE Copied from GCN 41532 (https://gcn.nasa.gov/circulars/41532). We report preliminary analysis from follow-up ESO VLT observations obtained by the ENGRAVE collaboration of SN 2025ulz (Stein et al., GCN 41414), which was discovered within the 3D localization region of the GW alert S250818k (LVK Collaboration, GCNs 41437, 41440). Starting on 2025-08-24 00:03:40 UT, we observed the field of SN 2025ulz using the ESO VLT UT4 (Yepun) equipped with the MUSE integral-field spectrograph. A series of 4x700 s exposures were taken for this observation. From a preliminary reduction, extraction of a spectrum at the position of SN 2025ulz reveals a continuum well detected over the full wavelength range of 5000 to 9000 Å. The spectrum shows a prominent broad feature which we interpret as a P-Cygni profile of the H-alpha line, similar to that observed in young type II or IIb supernovae. The peak of the emission and the absorption trough is consistent with the host galaxy redshift of z = 0.0848 (ENGRAVE GCN 41476, Karambelkar et al., GCN 41436) and an expansion velocity of around 12,000 km/s. There is weaker evidence for an H-beta P-Cygni profile. Plausible matches to young type II and IIb SNe are found with SNID-SAGE (Stoppa et al. in prep, a new enhanced, python version of SNID), although the transient object continuum is contaminated by the host and the absorption line strengths are therefore diluted. We suggest that SN 2025ulz is a type II supernova (of unconfirmed subtype at this point) and is therefore unrelated to S250818k. 2025TNSCR3373....1B
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
21859 2025-08-24 00:03:40 VLT-UT4 / MUSE 2800 Camila de Sa Freitas (ESO), Israel Blanchard (ESO), Sam Kim (ESO) Luca Izzo (INAF/OACn) ENGRAVE tns_2025ulz_2025-08-24_00-03-40_VLT-UT4_MUSE_ENGRAVE.txt Object

Comments

TNS
System

Object coordinates updated

Object coordinates updated according to AT-report 267746 of Group Pan-STARRS
Previous RA, DEC: 15:51:54.196, +30:54:08.55 (237.9758159, +30.9023752)
Updated RA, DEC: 15:51:54.201, +30:54:08.67 (237.97583781, +30.9024079686)