David's Astronomy - Astronomical Transients 2025

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Astronomical Transients - 2025

Transients
2024

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Transients
2025

This page documents observations and images of Astronomical Transients (AT) with discovery dates in 2025.
(Note: Supernovae in 2025 are presented on a separate page : SN 2025 )
(Note: Some images may roll over into the following year)

Galactic Transients (2025)
     Name, type, discovery date

AT 2025la - Transient (2025-01-11) (non-detection)

AT 2025lc - CV Type Transient (2025-01-10)

AT 2025lr - Afterglow Type Transient (2025-01-14) (non-detection)

AT 2025md - CV Type Transient, V1948 Cyg (2025-01-12)

AT 2025oj - CV Type Transient (2025-01-15) (non-detection)

Extragalactic Transients (2025)
     Name, type, discovery date, host galaxy (if relevant)

M31 Transients

M33 Transients

Other Extragalactic Transients

AT 2025fk - Transient (2025-01-03) in MCG -2-28-37

AT 2025hy - Transient (2025-01-01) in UGC 10913

Galactic Transients (2025)

AT 2025la - Transient (discovered 2025-01-11) (non-detection)

AT 2025la (Cygnus)
AT 2025la (Type: unk) discovered 2025-01-11.109 UT by Gaia
Alias: Gaia25acy
Discovery Magnitude 16.89 (orange-ATLAS Filter)
vs Prior Non-Detection Limiting Magnitude 19.34
[ TNS 2025la | Gaia25acy ]

AT 2025la - 2025-03-18 (T+66.0d)
Image below (2025-03-18.125) was taken 66.0 days after discovery of 2025la
Positon of earlier transient (not visible) is shown by white cross hairs.
Non-Detection Limiting Magnitude +18.5 (Clear Filter)

Annotated CCD Image (100% size, linear scale, cropped)
4 x 180s exposure (average combine), 3x3 binning, Clear Filter
2025-03-18 03:08 UT (#1302182-86)
12" LX200R (at f/10.4) + ST-10XME
Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2

AT 2025lc - CV Type Transient (discovered 2025-01-10)

AT 2025lc (Cygnus)
AT 2025lc (Type: CV) discovered 2025-01-10.553 UT by Gaia
Alias: Gaia25add
Alerting Magnitude 14.48 (G-Gaia Filter)
vs Historic Magnitude 15.89 +/- 0.61 SD
Outburst in candidate CV
( TNS 2025lc | Gaia25add )

AT 2025lc - 2025-03-15 (T+63.5d)
Image below (2025-03-15.080) was taken 63.5 days after discovery of 2025lc
Position of earlier transient (faint) is shown by white cross-hairs
Measured Magnitude +13.69 (Clear Filter)
Appears to be either still be in outburst (from Jan 10th)
or has started a new outburst.

Annotated CCD Image (100% size, linear scale, cropped)
5 x 60s exposure (average combine), 3x3 binning, Clear Filter
2025-03-15 01:58 UT (#1301164-68)
12" LX200R (at f/10.4) + ST-10XME
Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2

AT 2025lr - Afterglow Type Transient (discovered 2025-01-14) (non-detection)

AT 2025lr (Crater)
AT 2025lr (Type: Afterglow) discovered 2025-01-14.316 UT by MASTER
Alias: MASTER OT J110618.40-150641.1, GRB 250114A
Discovery Magnitude 15.9 (? Filter)
vs Prior Non-Detection Limiting Magnitude 19.7
Remarks: GRB 250114A optical counterpart
[ TNS 2025lr ]

AT 2025lr - 2025-03-17 (T+62.7d)
Image below (2025-03-17.995) was taken 62.7 days after discovery of 2025lr
Positon of reported transient (faded & no longer visible) is shown by white circle
Non-Detection Limiting Magnitude +18.5 (Clear Filter)

Annotated CCD Image (100% size, square root scale, cropped)
2 x 180s exposure (average combine), 3x3 binning, Clear Filter
2025-03-17 23:56 UT (#1302100-01)
12" LX200R (at f/10.4) + ST-10XME
Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2

AT 2025md - CV Type Transient, V1948 Cyg (discovered 2025-01-12)

AT 2025md (Cygnus)
AT 2025md (Type: CV) discovered 2025-01-12.882 UT by Gaia
Alias: Gaia25adm, V1948 Cyg
Alerting Magnitude 13.47 (G-Gaia Filter)
vs Historic Magnitude 14.94 +/- 0.65 SD
Outburst in known CV named V1948 Cyg
( TNS 2025md | Gaia25adm )

AT 2025md - 2025-03-15 (T+61.2d)
Image below (2025-03-15.072) was taken 61.2 days after discovery of 2025md
Position of earlier transient (faint but distinct) is shown by white cross-hairs
Measured Magnitude +12.49 (Clear Filter)
Star seems somewhat fainter than the magnitude measurement suggests
A very faint star lies directly adjacent to AT2025md

Annotated CCD Image (150% size, linear scale, cropped)
5 x 60s exposure (average combine), 3x3 binning, Clear Filter
2025-03-15 01:46 UT (#1301157-61)
12" LX200R (at f/10.4) + ST-10XME
Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2

AT 2025oj - CV Type Transient (discovered 2025-01-15) (non-detection)

AT 2025oj (Vulpecula)
AT 2025oj (Type: CV) discovered 2025-01-15.040 UT by Gaia
Alias: Gaia25aeh
Alerting Magnitude 15.86 (G-Gaia Filter)
vs Historic Magnitude 18.31 +/- 0.26 SD
Outburst in candidate eclipsing CV ZTF18abmnvsq
( TNS 2025oj | Gaia25aeh )

AT 2025oj - 2025-03-15 (T+59.1d)
Image below (2025-03-15.120) was taken 59.1 days after discovery of 2025oj
Position of earlier transient (not visible) is shown by white cross-hairs
Non Detection Limiting Magnitude +17.0 (Clear Filter)
Star seems to have faded back to within its normal magnitude range (+17.7 to +19.5, Gaia)
Propose to reschedule target using 5 x 180s frames for better chance of detection

Annotated CCD Image (125% size, linear scale, cropped)
3 x 60s exposure (average combine), 3x3 binning, Clear Filter
2025-03-15 02:55 UT (#1301194-96)
12" LX200R (at f/10.4) + ST-10XME
Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2

Extragalactic Transients (2025)

M31 Transients (2025)

M33 Transients (2025)

Other Extragalactic Transients (2025)

AT 2025fk - Transient (discovered 2025-01-03) in MCG -2-28-37

MCG -2-28-37 with AT 2025fk (Crater)
AT 2025fk (Type: unk) discovered 2025-01-03.523 UT by ZTF
Alias: ZTF25aaaqfrf
Discovery Magnitude 18.25 (orange-ATLAS Filter)
vs Prior Non-Detection Limiting Magnitude 18.76
( TNS 2025fk )

MCG -2-28-37 - Spiral Galaxy
MCG -2-28-37 / PGC 33211 (catalog mag +14.7)
with other galaxies in same FOV: PGC 33194 (catalog mag +15.4),
PGC 33178 (catalog mag +16.0), PGC 33179 (catalog mag +16.2)

Annotated CCD Image (50% size, square root scale)
5 x 180s exposure (average combine), 3x3 binning, Clear Filter
2025-03-19 00:23 UT (#1303095-99)
12" LX200R (at f/10.4) + ST-10XME
Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2

MCG -2-28-37 with AT 2025fk - 2025-03-19 (T+74.5d)
Image below (2025-03-19.010) was taken 74.5 days after discovery of 2025fk
Position of reported transient (not separately distinguishable) is shown by white cross-hairs
Measured Magnitude, Nucleus + SN +14.19 (Clear Filter)

Annotated CCD Image (150% size, square root scale, cropped)
5 x 180s exposure (average combine), 3x3 binning, Clear Filter
2025-03-19 00:23 UT (#1303095-99)
12" LX200R (at f/10.4) + ST-10XME
Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2

AT 2025hy - Transient (discovered 2025-01-01) in UGC 10913

UGC 10913 with AT 2025hy (Hercules)
AT 2025hy (Type: unk) discovered 2025-01-01.573 UT by ZTF
Using Palomar 1.2m Oschin Telescope
Alias: ZTF25aabaclh
Discovery Magnitude 18.29 (r-ZTF Filter)
( TNS 2025hy )

UGC 10913 - Spiral Galaxy

Annotated CCD Image (70% size, square root scale, cropped)
4 x 180s exposure (average combine), 3x3 binning, Clear Filter
2025-03-18 01:52 UT (#1302136-40)
12" LX200R (at f/10.4) + ST-10XME
Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2

UGC 10913 with AT 2025hy - 2025-03-18 (T+75.5d)
Image below (2025-03-18.072) was taken 75.5 days after discovery of 2025hy
Position of reported transient (very faint / barely detectable) is shown by white cross-hairs
Poor quality image (trailed stars)

Annotated CCD Image (150% size, square root scale, cropped)
4 x 180s exposure (average combine), 3x3 binning, Clear Filter
2025-03-18 01:52 UT (#1302136-40)
12" LX200R (at f/10.4) + ST-10XME
Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2

This Web Page:	Astronomical Transients - 2025
Last Updated :	2025-03-26
Site Owner :	David Richards
Home Page :	David's Astronomy Web Site

David's Astronomy Pages (Deep Sky) Astronomical Transients - 2025