The Box (Hickson 61)
History
The four galaxies were discovered by William Herschel on 11 April 1785. He listed them as faint nebula II 372 (NGC 4173) and very faint nebulae III 358 (NGC 4169), III 359 (NGC 4174) and III 360 (NGC 4175). For II 372 he noted: «One of 4. The most north of the preceding side of a quartille. faint, small.» And for the other three he noted: «Three of a quartile. The place is that of II 372. All very faint, very small and all within 3'.» [463]
In 1981 Paul Hickson presented his systematic search for groups of galaxies on the photo plates of the POSS to the public. In order to be classified by him as a galaxy group, at least four members should be identifiable, which had to be reasonably compact and isolated from the rest. This group is the 61st of a total of 100 included in the catalogue. [140]
The galaxy group Hickson 61 (HCG 61) also bears the nickname «The Box» (not to be confused with NGC 6309, Box Nebula). The name is appropriate because the four galaxies form approximately a rectangle to one another.
Physical Properties
The four galaxies in this group seem to show no trace of interaction.
The galaxy NGC 4169 in the southwest corner is of the compact type S0, the intermediate stage between a spiral galaxy and a barred spiral galaxy. We look at it from the side, because its axis of rotation is inclined by 70 degrees to our line of sight. The escape speed in relation to the local group is around 3800 km/s. With a Hubble constant of 75 km/s/Mpc, this means a distance of around 170 million light years. [134]
In the case of the elongated galaxy NGC 4173 in the northern corner, we look exactly at the edge, which makes it difficult to determine its type. In the Deep-Sky Field Guide to Uranometria 2000.0 [22] you can find the type SBd and in the Lyon-Meudon Extragalactic Database [134] the type Scd. Both are very open systems with sweeping spiral arms. NGC 4173 is moving away at a speed of only 1000 km/s, which equates to a distance of only 43 million light years. So it doesn't seem to belong to the group, but she still included Paul Hickson. NGC 4173 is also a bit out of line because of its low surface brightness.
NGC 4174 at the southern corner is by far the smallest of the four galaxies, but still much brighter than NGC 4173. In this spiral galaxy, too, we are almost looking at the edge, because the angle between the axis of rotation and the viewing direction is about 72 degrees. It shows the same escape speed as NGC 4169, so also the same distance. [134]
The galaxy NGC 4175 in the west of the group of four is a spiral galaxy of type S or Sb, roughly like M 31. The angle of inclination is 86 degrees, so we are almost looking at the edge. Their escape speed is somewhat higher with about 3900 km/s relative to the local group, which equates to a distance of 170 million light years. [134]
| Name | RA | Dec | Type | bMag | vMag | B-V | SB | Dim | PA | z | D(z) | MD | Dreyer Description | Identification, Remarks |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| NGC 4169 | 12 12 18.7 | +29 10 46 | Gx (S0) | 13.2 | 12.2 | 1.0 | 12.6 | 1.8 × 0.9 | 153 | 0.012622 | 53.31 | F, S, 1st of 4 | UGC 7202, MCG 5-29-32, CGCG 158-41, HCG 61A, The Box | |
| NGC 4173 | 12 12 21.5 | +29 12 26 | Gx (Scd) | 13.6 | 13.0 | 0.6 | 14.2 | 5 × 0.7 | 134 | 0.003759 | 15.88 | 9.700 | F, S, 2nd of 4 | UGC 7204, MCG 5-29-33, CGCG 158-43, KUG 1209+294A, HCG 61B, FGC 1382, The Box |
| NGC 4174 | 12 12 26.9 | +29 08 57 | Gx (S0-a) | 14.4 | 13.4 | 1.0 | 11.4 | 0.8 × 0.3 | 50 | 0.013493 | 56.99 | F, S, 3rd of 4 | UGC 7206, MCG 5-29-34, CGCG 158-44, KUG 1209+294B, ARAK 351, HCG 61D, PRC C-39, MK 761, The Box | |
| NGC 4175 | 12 12 31.0 | +29 10 07 | Gx (Sbc) | 14.2 | 13.3 | 0.9 | 12.8 | 1.8 × 0.4 | 130 | 0.013384 | 56.53 | F, eS, 4th of 4 | UGC 7211, MCG 5-29-36, CGCG 158-45, HCG 61C, IRAS 12099+2926, The Box |
Finder Chart
The galaxy quartet is not that easy to find among the vast numbers of galaxies in the Coma/Virgo cluster. About four degrees west and one degree north of 4.4 mag bright star γ Comae Berenices are started using a large field eyepiece to search for the star patterns shown in the 1° close-up. Since the quartet of galaxies appears faint and inconspicuous, an eyepiece with a field of view of around 15 arc minutes is recommended.
