2025yhj | Transient Name Server

RA/DEC (2000)

01:52:50.353 +15:55:53.45

28.2098038 +15.9315139

Type

SN II

Redshift

0.0255

Discovery Report Classification Report

Reporting Group

LAST

Discovering Data Source

LAST

Discovery Date

2025-09-22 22:03:02.592

TNS AT

Public

Discovery Mag

18.84

Filter

Clear-

Reporter/s

R. Konno (WIS), E. A. Zimmerman (WIS), A. Horowicz (WIS), S. Garrappa (WIS), E. O. Ofek (WIS), S. Ben-Ami (WIS), D. Polishook (WIS), O. Yaron (WIS), P. Chen (WIS), A. Krassilchtchikov (WIS), Y. M. Shani (WIS), E. Segre (WIS), A. Gal-Yam (WIS), S. Spitzer (WIS), and K. Rybicki (WIS) on behalf of the LAST Collaboration

NED SIMBAD DECaLS PanSTARRS-1 SkyMapper VizieR WISE DSS ADS

Light curves

Pointer position (MJD, Mag, Abs.Mag): (0.00, 0.00, 0.00)

Spectra

Select	ID	Obs-date (UT)	Tel / Inst	Observer/s	Reducer/s	Group	Spectrum ascii file	Spec. Type
	22186	2025-10-11 02:57:19	LT / SPRAT	Jacob Wise, Daniel Perley, K-Ryan Hinds, Zoe McGrath	Jacob Wise	ZTF	tns_2025yhj_2025-10-11_02-57-18.951_LT_SPRAT_ZTF.spec	Object
Binning factor: (rounded to nearest integer >1) Mouse hovers at WL: 0 (rest), 0 (observed) ▌Show H at z=v_exp= km/s ▌Show He at z=v_exp= km/s ▌Show He II at z=v_exp= km/s ▌Show C II at z=v_exp= km/s ▌Show C III at z=v_exp= km/s ▌Show C IV at z=v_exp= km/s ▌Show N II at z=v_exp= km/s ▌Show N III at z=v_exp= km/s ▌Show N IV at z=v_exp= km/s ▌Show N V at z=v_exp= km/s ▌Show O at z=v_exp= km/s ▌Show [O I] at z=v_exp= km/s ▌Show O II at z=v_exp= km/s ▌Show [O II] at z=v_exp= km/s ▌Show [O III] at z=v_exp= km/s ▌Show O V at z=v_exp= km/s ▌Show O VI at z=v_exp= km/s ▌Show Na at z=v_exp= km/s ▌Show Mg at z=v_exp= km/s ▌Show Mg II at z=v_exp= km/s ▌Show Si II at z=v_exp= km/s ▌Show S II at z=v_exp= km/s ▌Show Ca II at z=v_exp= km/s ▌Show [Ca II] at z=v_exp= km/s ▌Show Fe II at z=v_exp= km/s ▌Show Fe III at z=v_exp= km/s ▌Show Å at z=v_exp= km/s ▌Show Å at z=v_exp= km/s ▌Show Å at z=v_exp= km/s ▌Show Å at z=v_exp= km/s ▌Show Tellurics ▌Show Galaxy lines at z= ▌Show WR-WN at z=v_exp= km/s ▌Show WR-WC/O at z=v_exp= km/s Remarks
	22134	2025-09-30 22:18:40	LT / SPRAT	Robotic		GOTO	tns_2025yhj_2025-09-30_22-18-40.032_LT_SPRAT_GOTO.dat	Object
Binning factor: (rounded to nearest integer >1) Mouse hovers at WL: 0 (rest), 0 (observed) ▌Show H at z=v_exp= km/s ▌Show He at z=v_exp= km/s ▌Show He II at z=v_exp= km/s ▌Show C II at z=v_exp= km/s ▌Show C III at z=v_exp= km/s ▌Show C IV at z=v_exp= km/s ▌Show N II at z=v_exp= km/s ▌Show N III at z=v_exp= km/s ▌Show N IV at z=v_exp= km/s ▌Show N V at z=v_exp= km/s ▌Show O at z=v_exp= km/s ▌Show [O I] at z=v_exp= km/s ▌Show O II at z=v_exp= km/s ▌Show [O II] at z=v_exp= km/s ▌Show [O III] at z=v_exp= km/s ▌Show O V at z=v_exp= km/s ▌Show O VI at z=v_exp= km/s ▌Show Na at z=v_exp= km/s ▌Show Mg at z=v_exp= km/s ▌Show Mg II at z=v_exp= km/s ▌Show Si II at z=v_exp= km/s ▌Show S II at z=v_exp= km/s ▌Show Ca II at z=v_exp= km/s ▌Show [Ca II] at z=v_exp= km/s ▌Show Fe II at z=v_exp= km/s ▌Show Fe III at z=v_exp= km/s ▌Show Å at z=v_exp= km/s ▌Show Å at z=v_exp= km/s ▌Show Å at z=v_exp= km/s ▌Show Å at z=v_exp= km/s ▌Show Tellurics ▌Show Galaxy lines at z= ▌Show WR-WN at z=v_exp= km/s ▌Show WR-WC/O at z=v_exp= km/s Remarks

Light Curves

Filter

Tel / Inst

Obs-date range

JD Range

Photometry

wide-ATLAS

ATLAS-TDO_ATLAS-05

2025-09-21 01:18:22 - 2025-09-21 01:18:22

2460939.55442 - 2460939.55442

Photometry

ID	Obs-date	JD	Mag. / Flux	Err	Lim. Mag./Flux	Units	Filter	Tel / Inst	Exp-time	Observer/s	Remarks
519371	2025-09-21 01:18:22	2460939.55442			19	ABMag	wide-ATLAS	ATLAS-TDO_ATLAS-05	30	Robot	[Last non detection]

Clear-

LAST_LAST-Cam

2025-08-30 23:59:25 - 2025-09-22 22:03:03

2460918.4996 - 2460941.41878

Photometry

ID	Obs-date	JD	Mag. / Flux	Err	Lim. Mag./Flux	Units	Filter	Tel / Inst	Exp-time	Observer/s	Remarks
519233	2025-09-22 22:03:03	2460941.41878	18.84			ABMag	Clear-	LAST_LAST-Cam	400
519232	2025-08-30 23:59:25	2460918.4996			21	ABMag	Clear-	LAST_LAST-Cam	400		[Last non detection]

L-GOTO

GOTO-N_GOTO-1

2025-09-22 02:46:46 - 2025-09-24 02:28:51

2460940.615805 - 2460942.603371

Photometry

ID	Obs-date	JD	Mag. / Flux	Err	Lim. Mag./Flux	Units	Filter	Tel / Inst	Exp-time	Observer/s	Remarks
519464	2025-09-24 02:28:51	2460942.603371	17.89	0.05		ABMag	L-GOTO	GOTO-N_GOTO-1	180
519463	2025-09-22 02:46:46	2460940.615805			19.7	ABMag	L-GOTO	GOTO-N_GOTO-1	180		[Last non detection]

r-ZTF

P48_ZTF-Cam

2025-09-20 09:00:12 - 2025-09-20 09:00:12

2460938.8751389 - 2460938.8751389

Photometry

ID	Obs-date	JD	Mag. / Flux	Err	Lim. Mag./Flux	Units	Filter	Tel / Inst	Exp-time	Observer/s	Remarks
520972	2025-09-20 09:00:12	2460938.8751389			20.6254	ABMag	r-ZTF	P48_ZTF-Cam			[Last non detection]

g-ZTF

P48_ZTF-Cam

2025-09-24 09:15:08 - 2025-09-30 07:43:06

2460942.8855093 - 2460948.8215972

Photometry

ID	Obs-date	JD	Mag. / Flux	Err	Lim. Mag./Flux	Units	Filter	Tel / Inst	Exp-time	Observer/s	Remarks
520974	2025-09-30 07:43:06	2460948.8215972	17.4791	0.0393305		ABMag	g-ZTF	P48_ZTF-Cam
520973	2025-09-24 09:15:08	2460942.8855093	17.8448	0.04264		ABMag	g-ZTF	P48_ZTF-Cam

cyan-ATLAS

ATLAS-HKO_ATLAS-02

2025-09-23 10:30:16 - 2025-09-23 10:30:16

2460941.93769 - 2460941.93769

Photometry

ID	Obs-date	JD	Mag. / Flux	Err	Lim. Mag./Flux	Units	Filter	Tel / Inst	Exp-time	Observer/s	Remarks
519372	2025-09-23 10:30:16	2460941.93769	18.378	0.174	19.44	ABMag	cyan-ATLAS	ATLAS-HKO_ATLAS-02	30	Robot

AT Reports

ID	Time received (UT)	Sender	Reporter/s	Reporting group	Disc. Data Source	RA	DEC	Discovery date (UT)	Discovery Mag.	Filter	AT Type	Internal name	Assoc. Groups	ADS Bibcode	Unreal
271808	2025-09-30 10:04:27	Fritz	Jesper Sollerman (SU),Christoffer Fremling (Caltech),Daniel Perley (LJMU) et al.	ZTF	ZTF	01:52:50.353	+15:55:53.45	2025-09-24 09:15:08.003	17.8448	g-ZTF	PSN	ZTF25abtgvqq	ZTF		N
271107	2025-09-24 04:07:02	GOTO_bot	S. Belkin,G. Ramsay,K. Ackley et al.	GOTO	GOTO	01:52:50.346	+15:55:53.91	2025-09-24 02:28:51.168	17.89	L-GOTO	Other	GOTO25hpf	GOTO		N
271047	2025-09-23 20:31:13	ATLAS_Bot1	J. Tonry,L. Denneau,H. Weiland et al.	ATLAS	ATLAS	01:52:50.346	+15:55:53.53	2025-09-23 10:30:16.416	18.378	cyan-ATLAS	PSN	ATLAS25lvx	ATLAS		N
270982	2025-09-23 01:41:18	LAST_Bot1	R. Konno (WIS),E. A. Zimmerman (WIS),A. Horowicz (WIS) et al.	LAST	LAST	01:52:50.376	+15:55:53.61	2025-09-22 22:03:02.592	18.84	Clear-	PSN		LAST	2025TNSTR3824....1K	N

Classification Reports

Time received (UT)

Sender

Classifier/s

Group

Classification

Redshift

Spectra

Related files

Assoc. Groups

End prop. period

Remarks

ADS Bibcode

22186

2025-10-11 04:07:36

Jacob Wise

Jacob Wise (LJMU), Daniel Perley (LJMU), K-Ryan Hinds (Caltech), Zoe McGrath (LJMU)

ZTF

SN II

0.0255

ZTF

Spectrum displays broad H-alpha and H-beta in contrast to previously obtained featureless spectra, consistent with the evolution of a SN II. Redshift of z = 0.0255 ± 0.0035 obtained by fitting our spectrum to template spectra from previously classified SN II using Next Generation Superfit (NGSF, Goldwasser et al. 2022). Follow-up spectroscopic observations are encouraged to better constrain the transient's redshift.

2025TNSCR4077....1W

Related files

File	Comments	Last Modified (UT)	Modified By
tns_2025yhj_atrep_22186_ZTF.pdf	NGSF fits	2025-10-11 04:07:36	Jacob Wise

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
22186	2025-10-11 02:57:19	LT / SPRAT		Jacob Wise, Daniel Perley, K-Ryan Hinds, Zoe McGrath	Jacob Wise	ZTF	tns_2025yhj_2025-10-11_02-57-18.951_LT_SPRAT_ZTF.spec		Object

22134

2025-10-01 10:31:45

Miika Pursiainen

M. Pursiainen, D. O'Neill, T. Killestein, B. Godson, K. Ackley, M. J. Dyer, J. Lyman, K. Ulaczyk, S. Belkin, D. Steeghs, D. K. Galloway, V. Dhillon, P. O'Brien, G. Ramsay, K. Noysena, R. Kotak, R. P. Breton, L. K. Nuttall, D. Pollacco, J. Casares Vel'azquez, A. Kumar on behalf of GOTO collaboration

GOTO

Spectrum dominated by featureless, blue continuum, and exact classification cannot be determined. However, as the event is located on a faint, fairly extended galaxy and exhibits a light curve that is peaking in ~1week, we consider the object likely a SN.

2025TNSCR3953....1P

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
22134	2025-09-30 22:18:40	LT / SPRAT		Robotic		GOTO	tns_2025yhj_2025-09-30_22-18-40.032_LT_SPRAT_GOTO.dat		Object

Comments

Object coordinates updated

Object coordinates updated according to AT-report 271808 of Group ZTF
Previous RA, DEC: 01:52:50.346, +15:55:53.53 (28.2097757895, +15.9315363158)
Updated RA, DEC: 01:52:50.353, +15:55:53.45 (28.2098038, +15.9315139)

Object coordinates updated

Object coordinates updated according to AT-report 271047 of Group ATLAS
Previous RA, DEC: 01:52:50.376, +15:55:53.61 (28.209902045723, +15.931558101588)
Updated RA, DEC: 01:52:50.346, +15:55:53.53 (28.2097757895, +15.9315363158)

SN 2025yhj

Spectra

Light curves

Comments

Object coordinates updated

Object coordinates updated