M 60 (NGC 4649, Arp 116) Galaxy in Virgo

Located at: RA 12 hours 43 minutes 40 seconds, Dec +11 degrees 32 minutes 58 seconds

Note: The galaxy in the outer envelope of M 60 is NGC 4647 (UGC 7896)

There are two other small NGC galaxies to the SSW (lower right), west to east they are NGC 4638 (UGC 7880) and NGC 4637 (UGC 7881)

 M 60 is Size: 7.4' x 6.0' Magnitude: 9.8 blue Class: E2

NGC 4647 is Size: 2.9' x 2.3' Magnitude: 11.9 blue Class: SAB(rs)c

NGC 4638 and NGC 4637 are Size: 2.2' x 1.3' and 1.1' x 0.4' Magnitude: 12.1 blue and 14.8 Class: S0- sp and S0?

North is up

West to the right

Telescope:

 8" f5 Newtonian reflector

Camera:

 ST-8XME, self-guided, binned 1x1, temp -20c, camera control MaxIm DL 4.56

Image:

Lumicon Deep Sky filter, 210 minutes (21 x 10 minute subs), 06/12/13/2007

Processing:

CCDStack 1.2, Photoshop 7.0

Location:

 Rolling Roof Observatory, Thousand Oaks, CA 91360 (+34d 13m 29s -118h 52m 20s)

Notes: From the NGC / IC Project:

Contemporary Visual Observation(s) for NGC 4649

NGC 4649 = M60 = U07898 = MCG +02-33-002 = CGCG 071-016 = Arp 116 = VV 206 = PGC 
42831
12 43 39.8 +11 33 11
V = 8.8;  Size 7.4x6.0;  SB = 12.9;  PA = 105d

17.5": very bright, fairly large, diffuse halo, slightly elongated ~E-W, very 
bright core with a bright substellar nucleus.  Forms a double system with N4647 
which is almost tangent to M60 barely off the NW edge.

13": bright, very bright nucleus, slightly elongated ~E-W.

- by Steve Gottlieb
Historical Research Notes / Correction for NGC 4649
NGC 4649 = M 60.  See NGC 4637. - Dr. Harold G. Corwin, Jr.
Contemporary Visual Observation(s) for NGC 4647
NGC 4647 = UGC 07896 = MCG +02-33-001 = CGCG 071-015 = Arp 116 = VV 206 = PGC 
42816
12 43 32.5 +11 34 56
V = 11.3;  Size 2.9x2.3;  SB = 13.2;  PA = 125d

17.5": forms a close double with M60.  Located just off the NW edge 2.8' from 
the center of M60.  Fairly faint, pretty large diffuse halo, small brighter 
core.  Appears slightly smaller than M60 but clearly less concentrated.

- by Steve Gottlieb
Historical Research Notes / Correction for NGC 4647
NGC 4647.  Is NGC 4637 (which see) possibly an observation of this object?
 - Dr. Harold G. Corwin, Jr.
Contemporary Visual Observation(s) for NGC 4638
NGC 4638 = UGC 07880 = MCG +02-32-187 = CGCG 070-230 = CGCG 071-006 = N4667? = 
PGC 42728
12 42 47.4 +11 26 32
V = 11.2;  Size 2.2x1.4;  SB = 12.3;  PA = 125d

17.5": moderately bright, very elongated 5:2 WNW-ESE, fairly small, bright core, 
substellar nucleus.  Located between M59 and M60.

13": fairly bright, small, bright core, elongated.

- by Steve Gottlieb

=================================================================
NGC 4667 = N4638? = U07880 = MCG +02-32-187 = CGCG 070-230 = CGCG 071-006 = PGC 
42728
12 42 47.4 +11 26 32

See observing notes for N4638.  Identification suggested by Corwin.

Discovered by JH (h1421). Not found by Reinmuth, Frost, d'Arrest and Vogel.  As 
h described this object as bright, it seems likely that is a duplicate 
observation of a bright galaxy with a poor position although there is no galaxy 
near h's place.  Perhaps a fairly bright star appeared nebulous in poor seeing?  
In NGCBUGS, Corwin suggests "NGC 4667 is probably = NGC 4638 with a 2 minute 30 
second error in RA."

- by Steve Gottlieb
Historical Research Notes / Correction for NGC 4638
NGC 4637 and NGC 4638.  The brighter of the two galaxies now carrying these 
numbers was found by WH (he actually found it twice, so it has two entries in 
his catalogue).  The fainter, a much smaller spiral of fairly low surface 
brightness with a faint star superposed west of the nucleus, was seen only 
once in 1854 by Lord Rosse (or his observer), who noted only a "Double
nebula; faint nebulosity connects them."  Given this sparce description,
Dreyer assigned an approximate position to the fainter and called it NGC 4637,
giving NGC 4638 to WH's brighter object.  He also added a note in the NGC
suggesting that Lord Rosse had actually seen M60 (NGC 4649) and NGC 4647,
which are just 12 arcmin northeast.  This would explain why no other observers
(aside from LdR and Herman Schultz) recorded the object as a double nebula.

Schultz's observation is an interesting one.  He has an extensive note in
which he claims that the nebula is clearly double (in spite of relatively poor
seeing on the night of observation), nearly on the parallel, and with a star
of 10th magnitude north-preceding (which there indeed is; there is no such
star north-preceding N4647 and M60).  Like LdR, he says nothing about the
relative brightness of the objects, but records his surprise that neither of
the Herschel's noticed that the object was double and extended.  Curiously, he
gives measurements (on two different nights) of only one of the nebulae,
though he specifically mentions that the micrometer wire, aligned with the
equator, nearly bisected both objects.  His reduced position is that of NGC
4638, the brighter object.

In his Virgo Cluster survey, Schwassmann listed only one object here and
assigned it the first NGC number of the pair.  His description fits the
brighter object, however, and he noted that the identity was uncertain and
that the object could be NGC 4638 instead.  His position is peculiar, too: the
RA is that of the fainter eastern galaxy, while the declination is that of the
brighter western object.  Remembering that Schwassmann's plate was taken with
a 6-inch lens, I suspect that the plate recorded only the brighter object and
that Schwassmann made a measurement or reduction error in his RA.

Dreyer, however, had only Schwassmann's entry to go on, not a modern sky
survey.  So, he could not know about the potential problems in the Heidelberg
observation.  Thus, he adopted Schwassmann's observation as applying to the
fainter object, and put a note in IC2 to that effect.

My own guess, without Schultz's confirmation of the duplicity of the object,
would have been that Dreyer was correct in his supposition about LdR having
misidentified the objects he observed in 1854.  If this is the case, then NGC
4637 is a reobservation of NGC 4647 (found by JH) rather than the very faint
companion to NGC 4638.  However, Schultz's observation seems to clearly point
not to M60 and its companion, but N4637 and N4638.

Still, LdR and Schultz could have seen the fainter object -- both have others
just as faint in their lists -- especially since it is enhanced by the
superposed star, so the "classic" numbering for this pair of galaxies is
still a possibility.  I should note, too, that there has been some confusion
in the modern catalogues as to which number applies to which object.  Dreyer
unfortunately confused the issue a bit with his IC2 note, and also with his
original numbering:  JH had the fainter companion coming second in the GC.
Nevertheless, Dreyer clearly meant NGC 4638 to apply to WH's object, so that
is the identification I've adopted, leaving NGC 4637 as possibly applying to
the faint companion -- or to NGC 4647. - Dr. Harold G. Corwin, Jr.