HCG 003 – Group with one background member

HCG 003 has three galaxies at redshift ~7500 km/s and one galaxy at redshift ~11500 km/s. There doesn’t seem to be indicators suggesting that the higher redshift galaxy would not be a background galaxy accidentally positioned within group’s area.

Objects (NED search within 10 arcmin):
– PGC 002064, 7860 km/s
– PGC 002059, 11545 km/s
– MCG -01-02-032, 7302 km/s
– PGC 002043, 7804 km/s

Outside of the field shown in the figure above there are some additional interesting objects:
– SDSS J003440.06-073637.1, z = 0.507
– SDSS J003419.48-073149.5, z = 0.526
– LEDA 138198, 8017 km/s
– MCG -01-02-035, 7882 km/s
– Further out there are some additional high redshift objects (z = 0.14 … 2.27)

DRS: HCG 028

Higher redshift object (z = 0.101) within Hickson compact group 28 (z = 0.038) and very close to one of HCG 028 galaxies:

DRS: ESO 476-008

Three higher redshift galaxies around ESO 476-008:

SDSS J083531.06+245608.1 – very close discordant redshift galaxy pair

There is a higher redshift galaxy (SDSS J083530.81+245558.3, z = 0.267) very close to SDSS J083531.06+245608.1 (z = 0.073, see Figure below). Higher redshift might be projected within the disk of SDSS J083531.06+245608.1.

Figure 1. The objects with measured redshifts near SDSS J083531.06+245608.1. Image is from Sloan Digital Sky Survey.

Objects and their data

1 SDSS J083531.06+245608.1 galaxy 0.072907 16.5 (g) 0
2 SDSS J083530.81+245558.3 galaxy 0.266687 20.7 (g) 0.175

NED objects within 10′ from SDSS J083531.06+245608.1

ESO 534-021 – very close and bright high redshift companion

Projected very close to ESO 534-021 is higher redshift galaxy ESO-LV 5340211. There seem to be no obvious signs of interaction. It should be noted that further out (at 4.8 and 5.7 angular separation from ESO 534-021) there are two galaxies at similar redshift as ESO-LV 5340211.

One noteworthy thing about this system is that ESO-LV 5340211 is brighter than ESO 534-021 although ESO-LV 5340211 has about 6 times higher redshift (and therefore should be 6 times farther from us than ESO 534-021). I queried NED for galaxies between redshifts 18016 and 18216 (+/- 100 km/s from the redshift of ESO-LV 5340211). From resulting set of galaxies 1942 had nominal magnitude data (apparently) at same band as ESO-LV 5340211. Apparent magnitude of ESO-LV 5340211 is 14.66. Average apparent magnitude of the 1942 galaxies is 17.73. Standard deviation of the apparent magnitude of 1942 galaxies is 1.15. The apparent magnitude of ESO-LV 5340211 therefore deviates by about 2.7 sigmas from the mean apparent magnitude of the galaxies at its redshift.

It should be noted that of the 1942 galaxies, ESO-LV 5340211 is not brightest even if it is among the brightest. There are 13 galaxies that are brighter than ESO-LV 5340211. I checked the 13 galaxies and in one system (2MFGC 12636) there was similar situation that the high redshift galaxy was clearly brighter than nearby lower redshift galaxy. This is perhaps something to study in near future.

Figure 1. The objects with measured redshifts near ESO 534-021. Size of the image is 5 x 5 arcmin. Image is from Digitized Sky Survey.

Objects and their data

1 ESO 534-021 Sc 0.010474 (3140 km/s) 15.48 0
2 ESO-LV 5340211 galaxy 0.060428 (18116 km/s) 14.66 0.269

NED objects within 10′ from ESO 534-021

UGC 06003 – high redshift galaxy at the edge of the disk

Figure 1 shows UGC 06003 system. A galaxy with clearly higher redshift (object 2 in Figure 1) lies at the edge of UGC 06003’s (object 1 in Figure 1) disk. Apart from closeness to UGC 06003, there doesn’t seem to be any evidence suggesting that this apparent background galaxy would be anything else than a background galaxy.

Figure 1. The objects with measured redshifts near UGC 06003. Size of the image is about 3.4 x 3.4 arcmin. Image is from Sloan Digital Sky Survey.

Object 3 is quite well aligned across UGC 06003 with a similar looking object at the edge of Figure 2, but the object doesn’t have redshift available. In fact, there is a line alignment consisting of object 3, nucleus of object 1 (only roughly at the alignment line), object 2, yellow compact object, and then the object 3 counterpart.

Objects and their data

1 UGC 06003 S0/a 0.019410 (5819 km/s) 14.7 0
2 SDSS J105302.76+043800.8 galaxy 0.239829 20.4 (g) 0.288
3 SDSS J105309.72+043738.6 galaxy 0.463130 21.7 (g) 1.490
4 SDSS J105257.64+043726.9 galaxy 0.019277 17.9 (g) 1.612

NED objects within 10′ from UGC 06003

AM 0213-283 – higher redshift companion galaxy

AM 0213-283 was included to sample of Arp (1981). He reported his measurements of the redshifts in this system and noted:

The central object is a very disturbed spiral. High resolution photographs in the following paper indicate that the companion SE is on the end of a spiral arm, and the companion N is strongly interacting. The spectrum of the companion N shows strong, high excitation emission lines.

Companion N is the object 2 in Figure 2 and Table below. It has discordant redshift compared to the main galaxy (object 1). “Following paper” in quote above is Arp (1982). In that paper, Arp said of this system:

Note particularly the strong tail or jet curving out of companion B to the west. Most important of all, note the short spiral arm segments curving from the center of the disturbed spiral directly to companion B. Regardless of what the redshifts of the other galaxies in the vicinity may turn out to be, the evidence of interaction of companion B with the central galaxy is so strong, in my opinion, that the Δz = +14,021 km s-1 redshift discrepancy must be accepted as real and therefore as principally nonvelocity.

Figure 1 below shows an extract of the high resolution photograph presented in Arp (1982) of this system. I have added the marking of the discordant redshift “companion B”.

Figure 1. AM 0213-283 system from Arp (1982).

Sharp (1985) studied the interaction in the system and found no evidence of interaction between the main galaxy and the discordant redshift companion. Sharp did find evidence of interaction between the main galaxy and the non-discordant redshift companion. Sharp also measured redshifts of some nearby galaxies and found some of them to have similar redshift than the discordant redshift companion. Sharp’s conclusions:

The lack of any dynamical disturbance in the main galaxy near the anomalous companion B, contrasted with the disturbed arm stretching to the nonanomalous companion A, is clear evidence against any interaction between B and the main galaxy. For this reason alone, it is not necessary to postulate that the galaxy called B has a noncosmological redshift. In addition, at least two, and possibly three, nearby galaxies of small angular size have redshifts comparable to that of B, with similar emission-line structure in at least one, and probably two, of them. It seems that this system is a coincidental projection of a foreground interacting pair on a distant background group.


Figure 2 shows the objects with measured redshifts in the AM 0213-283 field. Object 7 also has similar redshift to AM 0213-283, so there seems to be a galaxy group at that redshift and not just an interacting pair.

Object 4 doesn’t belong to either galaxy group – it has redshift of about z = 0.3.

Figure 2. The objects with measured redshifts near AM 0213-283. Size of the image is about 7.5 x 7.5 arcmin. Image is from Digitized Sky Survey.

Objects and their data

1 AM 0213-283 Sc 0.035161 (10541 km/s) 15.11 0
2 [A81] 021344-2833N galaxy 0.082040 (24595 km/s) 0.231
3 [A81] 021344-2833SE galaxy 0.035948 (10777 km/s) 17.0 (r) 0.447
4 2QZ J021551.8-282321 galaxy 0.298000 20.29 0.982
5 2dFGRS S308Z130 galaxy 0.082200 (24643 km/s) 19.05 0.997
6 2dFGRS S307Z023 galaxy 0.082000 (24583 km/s) 19.20 1.087
7 LEDA 3210176 galaxy 0.035736 (10713 km/s) 17.96 1.211
8 2dFGRS S308Z127 galaxy 0.082914 (24857 km/s) 19.38 1.904

NED objects with measured redshifts within 10′ from AM 0213-283


Arp, H., 1981, Astrophysical Journal Supplement Series, vol. 46, May 1981, p. 75-112, “Spectroscopic measures of galaxies, their companions, and peculiar galaxies in the southern hemisphere”
Arp, H., 1982, Astrophysical Journal, Part 1, vol. 256, May 1, 1982, p. 54-74, “Characteristics of companion galaxies”
Sharp, N. A., 1985, Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 297, Oct. 1, 1985, p. 90-97, “Anomalous redshift companion galaxies – 0213-2836”

HCG 027 – galaxy line that couldn’t decide its redshift

Hickson Compact Group (HCG) number 27 is a line of five or six galaxies. There is only 5 objects within HCG 027 with redshift available in NED. Hickson et al. (1992) reported a sixth redshift for the system. They have there an object called “27f” with a redshift of 26100 km/s, while originally group had only five members 27a-e. This is object 6 in Figure 1 and table below. This additional galaxy is somewhat off from the line of five other galaxies.

HCG 027 was included to the sample of Mendes de Oliveira (1995) who studied discordant redshift objects in Hickson Compact Groups, and concluded that the results of the study supported the view of a cosmological origin for galaxy redshifts. However, Mendes de Oliveira found that “the distribution of positions for the discordant galaxies in quintets, however, is more centrally concentrated than that predicted for a uniform distribution of field interlopers,” and offered gravitational lensing as an explanation for the observation. Here we don’t explore this general compact group situation much further, and we concentrate on the HCG 027, but for another view of the general situation, an interested reader might take a look at Sulentic (1997).

So far, I haven’t found any paper that discusses HCG 027 as an individual discordant redshift system. The discordant redshift situation in the system is such that in the line there are two galaxies having radial velocity of cz ~ 18500 km/s, while three galaxies (and the additional sixth galaxy) have cz ~ 26000. In the traditional view this system is interpreted so that a pair of galaxies at cz ~ 18500 and group of background galaxies at cz ~ 26000 are accidentally aligned so that they seem to form a line (or a chain).

Figure 1 shows the objects with measured redshifts in the field of HCG 027, and data for the objects is given in the table below.

Figure 1. Objects with measured redshifts in/near HCG 027. Image is from Simbad.

Objects and their data

1 PGC 014863 SBc 0.061756 (18514 km/s) 16.44 0
2 2MASX J04192158-1142395 S0 0.086873 (26044 km/s) 18.74 0.910
3 PGC 014861 S0a 0.087581 (26256 km/s) 18.02 1.010
4 PGC 014870 Sa 0.087901 (26352 km/s) 17.50 1.813
5 PGC 014873 Sb 0.061176 (18340 km/s) 17.01 2.796
6 APMUKS(BJ) B041656.98-114846.3 S0 (26100 km/s) 19.46 0.519

NED objects within 10′ from HCG 027


Hickson et al., 1992, ApJ, 399, 2, 353-367, “Dynamical properties of compact groups of galaxies”

Mendes de Oliveira, C., 1995, MNRAS, 273, 1, 139-145, “The nature of discordant redshift galaxies in compact groups”

Sulentic, Jack W., 1997, ApJ, 482, 640, “The Twin Paradoxes of Compact Groups: Discordant Excess Muted but the Dynamical Puzzle Persists”

IC 2402 – QSOs, Galaxy, and a Radio filament

Note that this is a new version of IC 2402 post, original can be found here. There are some new redshifts in SDSS DR9 for this system (5 new QSOs), so it was time to do this post again. Only changes are in Notes section and in Figure 1 and Table 1.

Olsen (1970) studied the positions of 4C radio sources, and noted about radio source 4C 31.32:

The primary identification is the *13.5-mag E galaxy, NGC 2402 [should be IC 2402], which appears 3″E and 34″S of the radio position. An 18-mag blue stellar object appears 30″W and 17″N of the radio position.

Grueff & Vigotti (1974) studied the system further:

…the starlike object noted by Olsen was being studied by Schmidt, who found it to be a Quasar with a red-shift of 1.8 (Schmidt, private communication). The separation between the center of the galaxy and the Quasar is only less than a minute of arc.

In order to study the identification of the radio source, and the possible relationship between the galaxy and the quasar, they took new image and a radio map of the system. They found:

An inspection of Fig. 1 reveals that we are probably dealing with a double radio source with the two components symmetrical on each side of the parent galaxy, and showing considerable complexity.


There seems to be no evidence of any physical relation between the Quasar (marked by the arrow) and the radiosource.

They also noted that the double sided radiosource is normal in its dimensions at the redshift distance of IC 2402. New radio observations of the system was reported by van Breugel (1980), who noted some hot spots in the distribution of the radio material. Arp (1987) noted the situation:

As an example of a quasar connected to a galaxy by a radio filament we show in Fig. 8. In the northern lobe of the radio galaxy 0844+31 there is a hot spot only 5 arc sec distant from a high redshift, bright apparent magnitude quasar.

0844+31 being the IC 2402. He also gave probabilities for the association:

The chance of a quasar this bright falling this close to the hot spot is only 3×10-6. Even if we take the significant distance to be from the quasar to the center of the lobe, a distance of 19 arc sec, the chance is only 4×10-5.


Figure 1 shows the objects with available redshifts in IC 2402 field. I have kept the old numbering from the first version and I have added new SDSS DR9 objects numbered as S1, S2, S3,…

Objects 4 and 8 in Fig. 1 are quite well aligned across IC 2402.

Objects S1 and S2, both QSOs, are aligned across IC 2402. Object S2 is very close to a galaxy which has similar size as nearby object 3.

Objects 2 and S4, both QSOs, are aligned across IC 2402.

Objects 3, 6, 7, 9, and 10 in Fig. 1 are objects with similar redshift to IC 2402.

Figure 1. The objects with measured redshifts near of IC 2402. Size of the image is 10 x 10 arcmin. Image is from Sloan Digital Sky Survey (SDSS). Click image for larger version.

Objects and their data

1 IC 2402 galaxy, AGN 0.067373 14.9 (G) 0
2 [HB89] 0844+319 QSO 1.838570 19.1 (G) 1.001
S1 SDSS J084804.07+314703.8 QSO 1.04432 20.9 (G) 1.072
3 SDSS J084750.95+314755.7 galaxy 0.066607 18.2 (G) 1.893
4 SDSS J084800.96+314516.1 galaxy 0.143678 18.5 (G) 1.914
S2 SDSS J084749.38+314729.9 QSO 0.55262 21.6 (G) 2.084
5 SDSS J084809.99+314607.2 galaxy 0.144116 18.2 (G) 2.540
6 SDSS J084753.20+314437.5 galaxy 0.068520 18.1 (G) 2.803
S3 SDSS J084807.52+314912.9 QSO 1.70557 21.2 (G)
7 SDSS J084750.32+315119.2 galaxy 0.070321 17.3 (G) 4.574
8 SDSS J084755.36+315142.7 galaxy 0.375645 21.1 (G) 4.640
9 SDSS J084814.81+315054.5 galaxy 0.065922 18.5 (G) 5.044
10 SDSS J084738.84+315032.8 galaxy 0.068930 17.7 (G) 5.481
S4 SDSS J084811.42+314256.5 QSO 1.45813 20.9 (G)
S5 SDSS J084820.17+315014.9 QSO 1.33695 20.6 (G)

Objects in NED within 10 arcmin (and with redshift available).
SDSS image of the system.


Arp, 1987, IAUS, 124, 479, “Observations requiring a non-standard approach”

Grueff & Vigotti, 1974, A&A, 35, 491, “On the radiosource 0844 + 31 B”

Olsen, 1970, AJ, 75, 764, “Optical identification of radio source selected from the 4C catalogue”

van Breugel, 1980, A&A, 81, 275, “Multifrequency Observations of Extended Radio Galaxies – Part Two – B0844+31”

AM 0058-402 – bridged discordant redshift objects

Arp (1980) reported three new discordant redshift cases. One of the reported systems was AM 0058-402. This system has main galaxy (object 1) connected to an apparent companion (object 2) galaxy with a spiral arm-like bridge. Problem is that main galaxy has radial velocity cz = 6773 km/s while the companion has radial velocity 16415 km/s, so the difference in these velocities is too large for them to be physically connected in traditional view. Arp says this about the bridge:

On this latter higher-resolution photograph, it is seen that the connecting filament is in the nature of a spiral arm emerging from the larger galaxy. But the arm is much longer than any of the other arms in the galaxy, emerges orthogonally rather than tangentially from the main body, and terminates directly at the center of the companion.


Figure 1 shows nearest objects with measured redshifts in AM 0058-402 field.

– The bridged object, object 2, seems to belong to a group of galaxies at about 16500 km/s. Object 19 (which is just outside the pictured field) is brightest and seemingly largest of the galaxies in this group, and might be the main galaxy of the group. Objects in the group (within this field) are 2, 6, 7, 8, 11, 16, and 19.

– There seems to be another group at redshift z = 0.177. This group seems to be overlapping with the 16500 km/s group described above. Objects in this group are 9, 10, 13, 14, and 17.

– Objects 12 and 15 are roughly aligned across object 1. Object 3 also falls to their alignment line.

Figure 2. The objects with measured redshifts near AM 0058-402. Size of the image is about 15 x 15 arcmin. Image is from Digitized Sky Survey. Click for larger version of the image.

Objects and their data

1 MCG -07-03-005 spiral 0.022592 (6773 km/s) 14.5 0
2 PGC 003633 galaxy 0.054755 (16415 km/s) 15.6 (I) 0.426
3 ESP 40160 galaxy 0.105483 18.60 0.948
4 ESP 38602 galaxy 0.223564 19.21 2.551
5 ESP 38632 galaxy 0.115486 19.13 3.021
6 ESP 38526 galaxy 0.055215 (16553 km/s) 19.18 3.706
7 ESP 40626 galaxy 0.053981 (16183 km/s) 17.33 4.657
8 ESP 40625 galaxy 0.054845 (16442 km/s) 17.86 6.093
9 ESP 40187 galaxy 0.179334 18.29 6.479
10 ESP 40161 galaxy 0.177549 18.65 6.733
11 ESP 38528 galaxy 0.055582 (16663 km/s) 18.84 6.858
12 ESP 38482 galaxy 0.188030 19.38 6.875
13 ESP 38605 galaxy 0.176455 18.94 6.912
14 ESP 38669 galaxy 0.177936 18.99 7.119
15 ESP 38704 galaxy 0.107267 19.03 7.224
16 ESP 38529 galaxy 0.054858 (16446 km/s) 18.84 7.258
17 ESP 40188 galaxy 0.179994 18.72 7.799
18 [VCV2001] J010031.5-401351 QSO 0.610000 17.90 7.958
19 LEDA 101141 E 0.054948 (16473 km/s) 16.17 7.961
20 ESP 38483 galaxy 0.159123 18.95 8.449

NED objects within 10′ from AM 0058-402


Arp, H. 1980, Astrophysical Journal, Part 1, vol. 239, July 15, 1980, p. 469-471, 473, 474, “Three new cases of galaxies with large discrepant redshifts”