Quasars and Visibility of Their Host Galaxies

[Scott Harrington]

Hi All,

I've recently been trying to find a list of quasars that have their host galaxy also visible. Four that I know of are Mrk 231 in Ursa Major (HST image and 20-inch observation by Christian Busch), Mrk 421 in Ursa Major (14-inch observation by van Wulfen), Mrk 1502 in Pisces, and LEDA 33514 in Ursa Major. At the moment, I've only seen Mrk 1502 with my 16-inch.

This kind of research isn't easy since you tend to run across a lot of images like this (https://esahubble.org/images/opo9416b/). Also what's tricky is weeding out the Seyfert galaxies from the quasars. In Zadorozhna et al (2021), they state that "Historically, galaxies with active nuclei, where the luminosity of the nucleus does not exceed the luminosity of the host galaxy, are called Seyfert galaxies. If the luminosity of the active nucleus is much greater than the luminosity of [the] parent galaxy, such object is called a quasar." So, ones like Mrk 817 in Draco don't technically count even though the host galaxy is visible (20-inch observation by Christian Busch). Still, I'd be interested in a few of them, too. 

Scott

[Akarsh Simha]

Pardon me for an unresearched question: what counts as a quasar? Would a bright stellar Seyfert AGN count? If so check out NGC2681

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[Vishal Kasliwal]

Quasars vs Seyferts is a historical nomenclature thing. The text on AGN by Peterson might be a good starting point for understanding the AGN naming zoo. Also look up the Unified AGN model - Meg Urry's works night be of interest...

Vishal

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[Robin Hegenbarth]

Hi Scott et al.,

This is my first mail in this group, so I hope it works right away. :-) Scott, we seem to have very similar observing projects!

Indeed, the definition of a quasar seems to be subjective. Physically, they are very luminous examples of Seyfert galaxies, but the question is where to draw the limit between a quasar and an "ordinary" Seyfert galaxy.

In this catalog there is a list of quasars: https://ui.adsabs.harvard.edu/abs/2010A&A...518A..10V/abstract

They define a quasar as a starlike object or object with a starlike nucleus with broad emission lines that is brighter than -22.25 Mag absolute blue magnitude.

Interestingly, many objects listed in this catalog don't fulfill their magnitude criterion based on Simbad data, although they referenced Simbad data in their catalog.

Within the last couple of years I observed some of those objects. At least I Zw 1 (PGC 3151) and VII Zw 118 = PGC 20174 fulfill their criterion. With my 20" Dobsonian I was able to discern non-stellar galaxy bodies from their stellar cores when observing them.

At Deep Sky Meting in March 2026 in southern Germany I will give a presentation on this topic. So for readers who will attend (there certainly are a few...) I will discuss this quasar catalog and observations I did based on this source.

Clear skies,

Robin

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Virenfrei.www.avast.com

[Scott Harrington]

Thanks, Robin! I haven't made the charts yet, but I plan to view several this spring with my 16-inch telescope. Will be sure to report back.

Scott H>

[Steve Gottlieb]

Here are a few observations of quasar-like objects that Scott and Robin mentioned.

Steve

I Zw 1 = UGC 545 = PGC 3151
00 53 34.9  +12 41 36; Psc
V = 13.9-14.5;  Size 0.5'x0.5';  Surf Br = 12.3

17.5" (9/7/96): at 100x appears as a mag 13.5-14 "star" using a GSC finder chart to identify.  At 220x, the completely stellar core is surrounded by a much fainter 15" halo with averted vision.  The halo was easier to view at 415x.
******************************

VII Zw 118 = PGC 20174

07 07 13.1  +64 35 59; Cam
V = 15.3;  Size 0.4'x0.3'

24" (1/4/14): at 260x, appears as a faint mag 15-15.5 "star", though it was difficult to determine if it was quasi-stellar in soft seeing.  Easy to identify as it is located 1.4' WSW of mag 9.4 HD 52882 and there are no nearby stars of similar magnitude.

The V mag derived using SDSS photometry is 15.3, but the Veron 2010 catalogue of "Quasars and Active Galactic Nuclei" lists V = 14.6 and B = 15.3 with a classification of Quasar.
******************************

Mrk 421 = UGC 6132 = CGCG 184-050 = QSO 1104+384 = PGC 33452
11 04 27.3  +38 12 32; UMa
V = 12.8;  Size 0.8'x0.6';  Surf Br = 11.8

48" (4/23/25): at 610x and 813x; Mrk 421 appeared as an extremely bright 13th magnitude "star" (stellar nucleus) with a small, faint halo.  I tried to keep the intense glare of 6th mag 51 UMa outside the field. Mrk 421-5 = PGC 33453, just 14" ENE, appeared fairly faint, small, slightly elongated, ~12" diameter, low surface brightness.  UGC 6140, a diffuse edge-on was also visible to the S of a mag 7.5 star, as well as two fainter galaxies, PGC 33475 and LEDA 3765478.

18" (4/10/04): appears as a mag 12.7 "star" at 220x, though this is the core of a compact BL Lac object with a variable active nucleus (z = .03). A small, extremely faint halo was highly suspected at 220x (more secure at 300x) and the nucleus seems slightly softer than similar stars.  Located just 2' SSW of 6th mag star 51 UMa and 4' SW of a 7.5 mag star.

18" (5/31/03): at 350x, this compact galaxy appeared at an estimated mag 12.5-13.0 just 2' SSW of naked-eye mag 6.0 51 UMa and 4' SW of a mag 7.5 star!  Seeing too soft in breezy conditions to confirm a halo, though it was highly suspected.

17.5" (4/13/96): at 100x, appears as a nearly stellar 13 object situated just 2' SSW of 6th magnitude 51 UMa.  In comparison to similar foreground stars, this compact Markarian galaxy has a "soft" appearance with a very small and extremely faint halo.  Using a comparison sequence, this variable active nucleus appeared ~mag 13.3.

17.5" (5/22/93): appears as a mag 13.5 stellar object located just 2.1' SSW of 51 Ursa Majoris (V = 6.0) and 4' SW of mag 7.4 SAO 62392!  No halo seen at 220x.  This extremely compact galaxy has the most variable active galactic nucleus! (V = 12.4-14.0).
******************************

Mrk 231 = UGC 8058 = MCG +10-19-004 = CGCG 293-045 = CGCG 294-004 = A1254+57 = VII Zw 490 = PGC 44117
12 56 14.2  +56 52 25; UMa
V = 13.6;  Size 1.3'x1.0';  Surf Br = 13.7;  PA = 10°

24" (5/30/16): at 322x; this remarkable object (astrophysically) contains a bright quasi-stellar nucleus (mag ~13.5) surrounded by a small, very low surface brightness halo.  The appearance was very unusual as there was no core - just a bare bright nucleus that required a close look to verify it was slightly non-stellar (perhaps 3"-4" diameter).  The nucleus was surrounded by a small, dim halo.

Virenfrei.www.avast.com

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[Scott Harrington]

Thanks for sharing your observations, Steve! Seems you haven't viewed any of them with the size of telescopes that I currently own, so I've got my work cut out for me this Spring.

Scott H.

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[Steve Gottlieb]

By the way, I included Markarian 421 in the article “Blazar, Blazar, Burning Bright” with a theme of variable galaxies in the April 2010 issue of Sky & Tel. Several of these objects were discovered as variable stars, not galaxies!

The complete list of targets — Mrk 421, W Comae Berenices, AP Librae, Mrk 501, 3C 371, BL Lacertae, 3C 66A, and BW Tauri.

If anyone would like a copy of the article, send me a note.

Steve

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[Scott Harrington]

Yes, I'd be interested in a copy as I've never owned that issue nor read your article!

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[JayLEads]

I also would love a copy of that article, Steve. Interesting thread btw. 

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Thanks! 

Jay

[owen...@gmail.com]

Wolfgang wrote a booklet for the Webb Soc on extra galactic objects discovered as variable stars many years ago.

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[Alvin Huey]

I have a Variable Galaxy Observer's Guide, which I'm sure most of you are familiar with.  https://www.faintfuzzies.com/Files/VariableGalaxies%20v3.pdf

I'm actually starting to work on a revision of this one...since I built this guide a long time ago and haven't done anything with it since.

I have some observations from my 22" from about 17-20 years ago.  Just copied/pasted from my Master OR spreadsheet.

V1102 Cyg   19 10 37.2 +52 13 13

22" at 383x.  Picked up as a faint mag 16.5-17.0 stellar object.  It appears alf as bright as the two stars 20" north and 23" NNW.

BL Lac   22 02 43.3 +42 16 39

22" at 383x - Picked up as a stellar object. Suspected very faint halo, but not sure.  Half as bright as the star immediately to the east.

V395 Her  17 22 34.1 +24 45 00

22" at 383x - Very small, very faint, slightly fuzzy object.  

V396 Her. 17 22 41.2 +24 36 18

22” at 383, 460, and 639x – This object is stellar and very faint.  It was fainter than the nearby star stars visible in the 3.9’ field.  About half the brightness of both nearby 16.2 magnitude (red) stars located 0.8’ NE and 1.2’ SW.  I estimate the magnitude of this object to be about 16.8 to 16.9.

V362 Vul   20 02 48.6 +22 28 27

22" at 639x - Very faint Stellar object in a rich field of stars.  Needed a solid finder chart to identify the right object.  

UX Psc  01 11 45.4 +22 04 10

22" at 383x - Picked up as a very slightly fuzzy star. Did not detect the elongation.

S10721  00 38 33.1  +41 28 50 
22” at 383, 460, and 639x – This object appears slightly diffused with a stellar center.  Diffuse part is about 0.2' across.  Fainter than the mag 15.1 star that lies 0.9’ south and about the same as the mag 15.8 star.  

3C465  23 38 29.4  +27 01 54    3rd closest quasar at a distance at 129 Mpc.
22” at 306 and 383x – NGC 7720 is a bright, round glow with a much brighter center.  Very high surface brightness for a galaxy.  0.5’ across.  5 other galaxies are seen on the same 6.6’ field.  Starting with the closest, MAC 2338+2702B, is an extremely faint very small, round glow, detected 50% of the time using averted vision (AV).  MAC 2338+2701A is a considerably bright 2:1 elongated glow with a slightly brighter round center.  PA = 0 and 0.3’ long.  IC 5342  is a bright, small round glow with a brighter center.  0.3’ across.  IC 5341 and its western neighbor, CGCG 476-90, are equal in brightness and appearance.  Both are considerably faint round patches with brighter centers.  0.4’ across.

IO And   00 48 19.0. +39 41 09

22" at 306 and 383x - faint stellar object. Approx mag = 15.5

Hope this is helpful.

CS,

Alvin

[owen...@gmail.com]

After some internal discussions we decided we could release Wolfgangs guide as a free PDF so others could see the work.

 

Owen

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[Alvin H]

Thanks Owen for the resource!

Even though I referenced Wolfgang’s work, I don’t think I looked through it.  Anything that he writes is good, so I just put in the recommended resources.

CS,

Alvin

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[owen...@gmail.com]

Hopefully we will have the full version with cover up on the web site soon for download.

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[Alvin H]

I did a quick side-by-side, and I have a few missing.  

His work is amazing!  Definitely a go-to resource!  Thanks for sharing.  

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[Uwe Glahn]

Interesting topic. I have to visit some more objects from the lists.

 

Thanks for the .pdf Owen

 

From the four objects Steve mentioned, I can contribute two sketches:

http://www.deepsky-visuell.de/Zeichnungen/UGC6132_UGC6140.htm

http://www.deepsky-visuell.de/Zeichnungen/UGC8058.htm

 

uwe

 

From: Steve Gottlieb

Sent: Thursday, February 19, 2026 10:30 PM

To: adventures...@googlegroups.com

Subject: Re: [ADS] Quasars and Visibility of Their Host Galaxies

 

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[Muriel Dulieu]

I would like a copy of the article Steve, thank you!

I saw my first blazar at GSSP last year in Steve’s 24”. I don’t remember which one it was, 3C 273 in Virgo? But that is a quasar not a blazar since the jets are not perfectly aligned with us?

-Muriel

On Feb 22, 2026, at 12:22 AM, Uwe Glahn <ma...@deepsky-visuell.de> wrote:



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