5 replies to this topic

[Redbetter]

My contributions to this thread will be for newer supernovae not observed last month or earlier.  (Link to April 2025 SN thread.)  I generally only list ones that are viable targets for my aperture and latitude, and have to forego some early evening targets that are blocked by tall trees or in the light dome to the west of my normal observing site, so there will be some bright ones missing.  The primary source for supernova information is the Bright Supernova/Latest Supernovae page.  (This link sometimes goes dead, there is a mirror link.) There can be some delays on ones near or just past 17 mag, so I also use the ZTF Bright Transient Explorer link on that page and my own projections of peak magnitudes at times to look for candidates that have not yet been updated within the page.  ZTF explorer drops SNe typing in its table for weeks or months at a time, but this functionality has returned again recently, making it somewhat easier to screen again.  Sometimes the ZTF explorer links are not finding the TNS reports, so checking the Bright Supernova page can be helpful for that.

 

Here are some early candidates, the first one would be a real catch:

• SN 2025imr is a Type SLSN-I at z=0.09!  SLSN are 10x more luminous than other known supernovae, and the mechanisms for their creation remain diverse and speculative, with multiple types seen.  Suffice it to say, they are different.  They are also not very common (~28 total per year for the past decade) and are almost always at distances that defy visual observation with the 20".  z=0.09 is more distant than any of the other 514 SNe I have observed to date, only one is even close at 0.0815 and the closest after that is 0.0573.  Unfortunately, the SN is in Aquarius, so I'll have to wait a week for the Moon to get out of the way, and it is likely to fade by then.  ZTF had it 16.7 r mag on 5/12/25. The galaxy is too dim to be observed.
• SN 2025iqz is a Type Ia in a galaxy (pair?) too dim to observe (18+?) in Serpens.  The SN has reached about 16.3 magnitude as of 5/15/25.  Higher res images place the SN on/near a stream E of what appears to be an extremely tight pair of galaxy cores.
• SN 2025imw is a Type Ia near ESO 597-23 in Capricornus.  It was around 16.5 mag on 5/15/25.
• SN 2025kfm is a Type Ia on the SE edge of IC 4408 in Bootes.  It is around 16.8 mag as of 5/15/25 and has brightened, although based on the redshift it is unlikely to get much brighter.  

 

[Redbetter]

There is another one that is brightening and could become brighter than 17.

• SN 2025jus is a Type Ia in CGCG 47-101 in Virgo.  It is located off the extreme NE end of the galaxy. It reached 17.3 g mag on 5/15/25 per ZTF.  It should peak within the next five nights, and the redshift indicates it could reach somewhere between 16.6 and 17.  

[Redbetter]

Adding to the list:

• I was able to get to my dark site early enough in the evening of 5/20/25, and in position so that the 20" wasn't blocked by taller trees to the west.  This allowed me to see SN 2025kid, a Type Ia in IC 2567 in Leo.   At 278 and 357x the galaxy was logged as "xF, vvS, ave SB, primarily seeing main axis bar 2:1 elong SW/NE, and slight round glow of envelope, core bulge brighter with xxxF semi-stellar center."  SN "barely visible in AV, dimmer than galaxy center, just vague indication at 278, confirmed at 357x."   ZTF indicates it was around 16.75 g mag at the time.

More, new targets to try later:

• SN 2025kyg is a Type Ia in NGC 7753 in Pegasus.  This one is at presently at 15.7 mag about 23" NE of center on the spiral, so not difficult once the Moon is finally out of the way around 4am.  

On the evening of 5/19/25 I was able to see the following listed  in earlier posts: SN 2025iqz, SN 2025jus and SN 2025kfm, so I can confirm they are viable targets--I'll try to post the observations later.

 

[Redbetter]

Another one that looks promising:

• SN 2025krk is a Type Ia in CGCG 136-89 in Serpens.  The SN is only about 1+" NE of the galaxy center, but the galaxy center is not stellar in character, so the SN should be recognizable.  It had risen to ~16.2 r mag on 5/24/25.

[Redbetter]

Observations from evening of 5/20/25 with 20":

• SN 2025jus is a Type Ia in CGCG 47-101 in Virgo.  I described the galaxy as "xF, ave SB, xS (portion seen) SW/NE oval w/ xxF stellar core, not seeing outer portions but do see SN 2025jus well NE of visible glow" at 357x.  Per ZTF it was peaking around 17.0 V mag at the time.
• SN 2025kfm is a Type Ia on the SE edge of IC 4408 in Bootes.  I described the galaxy as "vvS, xF, ave SB, ~2:1 NW/SE w/ decent brightening to mid, but core not quite stellar".  Had some hint of SN at 278x, confirmed as stellar on SE edge of galaxy at 357x.  Per ZTF it was peaking around 16.5 mag at the time.  I was also able to barely see a companion galaxy just S of the IC, PGC 214251:  "xxxF, xxS".
• SN 2025iqz is a Type Ia in Serpens with galaxy far too dim to see.  This SN was seen readily at 278x preceeding a pair of 10.2/11.1 mag stars.  It was about 16.2 mag at the time.

[Redbetter]

On the evening of 5/27/25 I was able to observe a couple, and finally go after the two morning SN, unfortunately, the SLSN-I was a miss:

• SN 2025krk is a Type Ia in CGCG 136-89 in Serpens.  The SN was seen easily at 278x as ~mid 15 mag glow on the center of the galaxy.    This estimate is confirmed by ZTF putting it at 15.6 g mag at the time.
• SN 2025kyg, the Type Ia in NGC 7753 in Pegasus was up next.  It was seen with certainty at 278 and 357x 23" NE of center on the spiral.  I used positions of 15.6 and 16 mag stars to identify its position.  I could see it, the other marker stars and the galaxy core at the same time.  I estimated it was 16+ mag...but it turns out that two of the marker stars were dimmer than I thought (and listed) so my estimate should have been brighter.  ZTF has a bit of a gap, but it would have been 15.6 to 15.7 V mag at the time. 
• SN 2025imr, the SLSN-I in Aquarius was just too low to have much chance at, since the seeing was problematic that low.  I tried but was struggling with mid/high 16 mag stars at 500x, and it had faded to about 17.6 g mag at the time per ZTF.  I had only a couple of vague hints.
• SN 2025imw, the Type Ia has been correctly attributed to 2MASX J20404273-2026279 in Capricornus rather than nearby ESO 597-23 as previously listed.  I was able to detect both and I saw some elongation of the 2MASX suggestive of the presence of its even dimmer companion on the east edge, but not resolved.  My first pass at the SN failed, and I had to wait for it to get higher in the sky to finally start getting indications of it at 500x in line with a 16 and 16.9 pair to the NW.  It was still marginal, but appears real since I repeated it several times.  ZTF shows it fading rapidly in the green, but not in the red, so it was likely 17.5 V mag or a little brighter at the time.  Those green mags look suspect...