Galaxy Pairs and Star Formation Activity in Hickson Compact Groups

25 NRIAG Journal of Astronomy and Astrophysics, Special Issue, PP.339–361, (2006)

____________________________________________________________________ *National Research Institute of Astronomy and Geophysics, Helwan, Cairo, Egypt.

GALAXY PAIRS AND STAR FORMATION ACTIVITY IN HICKSON COMPACT GROUPS

Ibrahim Selim*, Gamal. Bakr*,

Hamed Ismail*, Ahmed Essam*, Ali Haroon* ABSTRACT: The effect of galaxy interaction on star formation in dense environment through the far-infrared emission (FIR) of galaxies has been investigated using data of Hickson Compact Groups (HCGs). We have identified 470 galaxy pairs with proximity criterion cr ≤ 390, and 358 galaxy pairs with (rp) less than 100 Kpc and ∆∆∆∆V ≤ 350 km/s. We identified 41 close galaxy pairs with projected separations (rp) less than 25Kpc and difference in velocity ∆∆∆∆V ≤ 100 km/s. The star formation rate (SFR) of galaxies in galaxy pairs is found to be enhanced for close galaxy pairs. The large fraction of star formation activity is probably due to the activity in the exchange of matter between the companions. The catalogue of galaxy pairs in HCGs has been established.

INTRODUCTION From the theoretical point of view, interactions between galaxies have been investigated using both analytical and computer models. The first numerical simulations of galaxy interactions, built by Toomre (1976) show that many observed characteristics, such as morphological type, could be explained by these processes. Toomre and Toomre et al. (1972) argued that collisions of galaxies in groups and clusters could lead to galaxy merging with the formation of elliptical galaxies. This conclusion was confirmed later in numerical simulations by Schweizer (1989). Barnes (1990), who found that the observations and numerical simulations of galaxies gave evidence of effective interactions, collisions and merging which continued to reshape and feed galaxies up to the present days. Barnes et al (1996) and Mihos et al (1996) concluded that the interactions between systems may induce gas inflows to the central region of the systems, triggering starburst. Different observations have shown that galaxy interactions and merging are powerful mechanisms to trigger star formation in galaxies (e.g. Larson et al. 1987; Donzelli et al 1997; Ellingson 1995; Pastoriza 1997 and Kennicutt et al 1998). The interactions during close encounters could be correlated with enha

GALAXY PAIRS AND STAR FORMATION ACTIVITY IN ….. _______________________________________________________________________

_______________________________________________________________________ 340 NRIAG Journal of Astronomy and Astrophysics, Special Issue,, (2006)

ncements of the star formation activity. In the local universe observations show that the merging and interactions of galaxies enhance star formation precesses in these galaxies and star formation activity is dependent on relative proximity and environment. (e.g. Barton et al. 2000; Patton et al. 2002 ; Le Fèvre et al. 200l ; Lambas et al. 2003 and Alonso et al 2005). Compact groups (CGs) of galaxies provide ideal laboratories for studying galaxy-galaxy interactions and star formation activity; they constitute a unique environment to study galaxy interactions because of their high space density and low velocity dispersion (Hickson et al. 1992). Apparent densities do not only exceed the values seen in the cores of rich clusters of galaxies, but their small populations (less than 10 bright galaxies per group) make an analysis of tidal features and diffuse optical light much simpler than in core of the cluster. The aim of this work is identifying true galaxy pair and study the star formation activity among these true pairs, as a function of both relative projected distance and relative radial velocity. In section 2, the sample of HCGs and the applied criterion are given. In section 3, the SFR among the components of true pairs in the HCGs is analyzed. Discussion of the results is outlined in section 4.

CATALOGUE OF GALAXY PAIRS AMONG HCGs Lambas et al (2003) and Ali (2000) criteria are both used to identify the galaxy pair in the first large homogenous sample of CGs of galaxies (Hickson, 1982, Hickson et al 1992). The value of cr = 390 was found by Ali (2000) to be the statistical discriminator between true pairs and false one. Therefore, pairs with cr ≤ 390 are considered to be true galaxy pairs, while the pairs having cr > 390 are considered to be false pairs. True galaxy pairs with cr≤ 130 are considered close pairs.

Ibrahim Selim et al. _______________________________________________________________________

_______________________________________________________________________ 341NRIAG Journal o f Astronomy and Astrophysics, Special Issue, (2006)

The criterion, cr, is defined as: cr = rs/re, (1) rs = H0-1(vi2 + vj2 –2 vi vj cosθ)0.5, (2) re = rei + rej (3) where vi and vj are the radial velocities of the two components whose angular separation is θ, rei and rej are the equivalent radii of the two components of the pair. Lambas et al (2003) identified the galaxy pairs with enhanced star formation activity according to velocity difference (∆V) and projected separation (rp). They adopt a reliable upper limit to select galaxy pairs at the values of rp ≤ 100 Kpc and ∆V ≤ 350 km/s, while close pairs are identified with rp ≤ 25 Kpc and ∆V ≤ 100 km/s. Our sample is the first large homogenous sample of compact groups of galaxies, (Hickson, 1982, Hickson et al 1992). The discordant radial velocity galaxies in HCG are excluded from our sample. some groups were rejected because they have fewer than three galaxies with confirmed accordant velocities. The remaining sample contains 91 compact groups of galaxies, each group contains at least three galaxies (Hickson1992, and the references their in ). The value of huplle constant, H0 = 100 km s-1 Mpc-1 is assumed thorough the paper.

The catalogue of true galaxy pairs in HCGs is filtered using the criteria of Ali, (2000) and Lambas et al. (2003). Our result is a list of 470 galaxy pairs with cr ≤ 390 according to Ali, (2000) and 358 galaxy pairs according to Lambas et al (2003) criteria with ∆V ≤ 350 km/s, rp ≤ 100 Kpc, 41 of them close galaxy pairs according to ∆V ≤ 100 km/s, rp ≤ 25 Kpc. The catalog of galaxy pairs is listed in Table1. The entitles of Table 1 are as follows: Column (1) group number followed by components identification, column (2) the mean distance of the pair's components in Mpc, column (3) angular separation between the pair's components in arcsec, column (4) absolute value of radial velocity difference ∆V, column (5) the mean projected separation between the pair's components rp (Mpc), column (6) the spatial separation between the pair's components rs (Mpc) and column (7) the cr-value for each pair.



STAR FORMATION ACTIVITY

When a galaxy interacts with another galaxy, its disk becomes gravitationally unstable. This instability induce a non-axisymmetric distortion such as a bar, which drives gas of the disk into the circumnuclear region, Mathew et al. (1996). The final true galaxies pair catalogue in HCGs allows a detailed study of the possible effects of the interactions in dense environment on the star formation rate (SFRs). So consequently we have estimated (SFRs) for true galaxy pairs in HCGs. The FIR-luminosity have been used to estimate the SFR. An equation for the SFR derived from the FIR luminosity was given by Thronson, et al. (1989) as follows: SFRFIR (M� yr-1) = 6.5 *10-10 * LFIR(L�), where LFIR(L�) is the luminosity of FIR from the IRAS observation in 60 µm and 100 µm bands and is estimated from the following equation (Thronson, et al.1991), LFIR(L�) = 6 * 105 (2.58 S60 + S100 ) D2, Where S60 and S100 are the IRAS flux densities in Jy at 60 and 100µm respectively, D is the distance in Mpc. The values of SFR are estimated for some galaxies in HCGs using the IRAS observation in 60 and 100 µm given by (Allam et al.1996). The interaction-star formation activity relation is studied by computing the mean star formation rate of galaxy pairs. We found that the star formation as a function of rp increases for closer galaxy pairs, (Fig1b). A similar behavior is found for the relative radial velocity difference ∆V (Fig.2). Figure 3 shows the SFR as a function of cr. A negative weak correlation is found between the reliable upper limits of the galaxies pair for the rp, ∆V and cr with SFR for the true pairs. The total SFR (sum of SFR of both components in each pair) is represented on log-scale as the y-axis versus the corresponding rp, ∆V and cr as the x-axis in all Figures.



Fig. 1: Total SFR as a function of rp-values for

(a) all galaxy pairs and (b) close pairs.

Fig. 2: Star formation rate against ∆∆∆∆V.

0 20 40 60 80 100

0.1

1

10

100SF

R

rp-in Kpc

4 8 12 16 20 24 28

0.1

1

10

100

SFR

rp-in Kpc

(a) all pairs (b) close pairs

(b) close pairs (a) all pairs



Fig. 3 Star formation rate against Cr.

DISCUSSION AND CONCLUSION To investigate the dependence of specific star formation rate on true pairs we consider firstly the dependence of SFR on rp separation, looking subsequently at the dependence on ∆V. We present a catalogue of 470 galaxy pairs from the sample of HCGs according to Ali (2000) criteria with cr ≤ 390. The galaxy pairs selected according to the observational criteria of Lambas et al (2003) are 358galaxy pairs with ∆V ≤ 350 km/s, rp ≤ 100 Kpc. We found 41 of them close galaxy pairs according to ∆V ≤ 100 km/s, rp ≤ 25 Kpc. This catalogue is given in Table 1. These results agree with previous studies of galaxies interaction (Plana et al. 1998, 2003; Allam et al 1996; Amram et el. 2004). The mean specific star-formation rate is found to be enhanced for projected separations of less than 25 kpc. The specific star-formation rate is found to decrease with increasing velocity difference. This is interpreted as being due to the presence of tidally-triggered nuclear starbursts in close pairs. There is also a trend showing the increase of the star formation activity with proximity between the compenets. From our result we conclude that:

1- Galaxy pairs show weak correlation between star formation activity and proximity between the compents.

2- Close galaxy pairs show significant correlation between star formation activity and proximity to a companion. We found the

0 100 200 300 400

0.01

0.1

1

10

100

SFR

Cr0 40 80 120 160

0.1

1

10

100

SFR

Cr

(b) close pairs (a) all pairs



star formation in close pair is similar to that found by Barton et al. (2000) and Lambas et al. (2003)

3- We found that the star formation rate appears to be a weaker function of projected physical separation than the velocity difference.

Table 1: The Catalog of Galaxy Pairs in HCGs.

GN

(1)

D (Mpc)

(2)

θ "

(3)

|∆∆∆∆v| km s-1

(4)

rp (Mpc)

(5)

rs (Mpc)

(6)

cr

(7) 1ab 103 26.96 29 0.0134 0.2903 13.442 1ad 102 111.9 117 0.0552 1.1713 61.946 1cd 101 59.47 64 0.0291 0.6407 76.76 1ac 101 171.2 181 0.0842 1.812 86.325 1bd 102 98.68 146 0.0487 1.4608 163.15 1bc 102 156.3 210 0.077 2.1014 190.42 2ab 43.5 79.88 40 0.0168 0.4004 39.641 2ac 42.8 256.3 91 0.0532 0.9116 83.408 2bc 43 310.7 131 0.0648 1.3116 142.78 3bd 78.3 228.1 56 0.0866 0.5666 63.713 4ad 81.6 147.1 118 0.0581 1.1814 64.146 5ab 122 23.5 74 0.0139 0.7401 29.828 5bc 124 66.07 268 0.0396 2.6803 140.41 5ac 123 45.86 342 0.0274 3.4201 149.08 6bd 114 41.17 57 0.0228 0.5705 51.26 6ab 115 54.66 292 0.0305 2.9202 220.15 6ad 116 95.57 235 0.0535 2.3506 249.56 6bc 112 16.79 410 0.0091 4.1 260.56 7ab 42.2 189.1 28 0.0387 0.2827 17.98 7ad 41.6 129.1 94 0.026 0.9404 61.811 7bc 43 318.8 128 0.0665 1.2817 75.337 7ac 42.9 322.6 156 0.067 1.5614 83.59 7bd 41.8 77.82 122 0.0158 1.2201 90.065 7cd 42.4 266.8 250 0.0548 2.5006 151.5 8ab 160 50.25 48 0.0389 0.4816 18.143 8ad 162 38.67 327 0.0303 3.2701 112.51 8bd 162 68.6 375 0.0537 3.7504 186.41



GN

(1)

D (Mpc)

(2)

θ "

(3)

|∆∆∆∆v| km s-1

(4)

rp (Mpc)

(5)

rs (Mpc)

(6)

cr

(7) 8cd 167 40.99 746 0.0332 7.4601 340.28

10cd 46.4 320.4 40 0.072 0.4064 43.679 10ab 50.1 508.3 286 0.1233 2.8627 106.1 10bc 47.6 496.9 202 0.1146 2.0232 114.2 10bd 47.4 637.7 242 0.1465 2.4244 162.19 10ac 49 189.7 488 0.0451 4.8802 228.71 10ad 48.8 151.3 528 0.0358 5.2801 284.34 12ae 144 85.61 62 0.0599 0.6229 36.125 12ad 143 75.1 166 0.0521 1.6608 79.497 12ac 145 97.31 162 0.0683 1.6214 85.32 12ce 145 153.7 100 0.1081 1.0058 104.73 12de 144 142.2 228 0.0989 2.2821 198.59 12ab 147 111.4 549 0.0793 5.4906 228.82 12bc 148 55.33 387 0.0396 3.8702 236.61 12cd 144 26.84 328 0.0187 3.2801 247.49 12be 147 133.7 487 0.0953 4.8709 333.74 13cd 122 84.1 31 0.0498 0.314 38.887 13bd 122 94.95 109 0.0559 1.0914 75.392 13ae 125 89.92 124 0.0546 1.2412 82.348 13bc 122 26.9 140 0.0159 1.4001 88.663 13ac 124 83.94 229 0.0503 2.2906 146.35 13ab 123 57.04 369 0.034 3.6902 167.33 13ad 123 134 260 0.0801 2.6012 181.44 13be 123 56.37 493 0.0337 4.9301 324.07 14bc 52.6 103.3 220 0.0263 2.2002 373.16 15df 62.4 34.58 2 0.0105 0.0226 2.1749 15ce 72.1 247.6 25 0.0865 0.2645 17.129 15be 71.6 131.4 80 0.0456 0.8013 50.816 15bc 71.7 150.4 105 0.0523 1.0513 60.656 15ab 70.4 340.4 150 0.1161 1.5045 83.377 15ae 70.8 454.2 230 0.1559 2.3053 142.69 15ac 70.9 208.8 255 0.0718 2.551 143.97 16cd 38.5 149.6 4 0.0279 0.0488 4.4942



GN

(1)

D (Mpc)

(2)

θ "

(3)

|∆∆∆∆v| km s-1

(4)

rp (Mpc)

(5)

rs (Mpc)

(6)

cr

(7) 16bc 39.1 269.3 126 0.0511 1.261 107.26 16bd 39.1 376.5 130 0.0714 1.302 107.46 16ab 40.6 61.49 175 0.0121 1.75 131.62 16ad 40 318.8 305 0.0618 3.0506 246.18 16ac 40 207.8 301 0.0403 3.0103 250.16 17ac 182 22.91 4 0.0202 0.0448 2.8956 17be 179 42.43 72 0.0369 0.7209 69.626 17ad 182 40.09 104 0.0353 1.0406 80.292 17cd 182 53.9 100 0.0475 1.0011 101.18 17ab 181 24.61 324 0.0215 3.2401 190.18 17bd 180 27.35 220 0.0239 2.2001 192.11 17ae 181 31.78 252 0.0279 2.5202 212.45 17bc 181 28.25 320 0.0247 3.2001 229.04 17de 181 67.35 148 0.0589 1.4812 235.95 17ce 181 14.28 248 0.0125 2.48 281.91 20ab 145 38.21 53 0.0268 0.5307 47.997 20ef 143 30.46 32 0.0211 0.3207 51.136 20be 144 63.15 112 0.044 1.1209 139.15 20ae 144 66.39 165 0.0463 1.6506 173.24 20bf 144 62.48 144 0.0435 1.4407 184.7 20af 144 81.54 197 0.0568 1.9708 212.53 21de 88.4 106.7 8 0.0457 0.0921 6.6348 21ab 75.9 271.3 46 0.0998 0.4707 23.737 21bc 74.6 621.9 212 0.2249 2.1319 102.35 21ac 74.9 392.4 258 0.1423 2.5839 136.4 23bc 49.7 150.7 95 0.0363 0.9507 81.072 23ab 48.6 269.5 123 0.0635 1.2316 90.793 23ad 46.8 307.8 236 0.0698 2.361 272.07 23ac 49.1 417.8 218 0.0993 2.1823 274.69 23bd 47.4 249.4 359 0.0573 3.5905 288.16 24ac 92.7 36.38 35 0.0163 0.3504 27.715 24ce 93 80.12 40 0.0361 0.4016 60.947 24ab 91.9 111.7 111 0.0497 1.1111 66.318



GN

(1)

D (Mpc)

(2)

θ "

(3)

|∆∆∆∆v| km s-1

(4)

rp (Mpc)

(5)

rs (Mpc)

(6)

cr

(7) 24ae 92.9 44.83 75 0.0202 0.7503 73.173 24bc 92.1 147.8 146 0.066 1.4615 111.64 24be 92.3 68.18 186 0.0305 1.8602 173.82 24bd 89.6 51.73 358 0.0225 3.5801 326.87 25af 62.8 201.6 6 0.0614 0.0858 7.743 25bd 64 107.3 7 0.0333 0.0775 7.8479 25ab 63.5 235 123 0.0723 1.2321 81.046 25ce 109 16.45 101 0.0087 1.01 83.104 25ad 63.4 274.1 116 0.0842 1.1631 111.15 25bf 63.4 33.81 129 0.0104 1.29 122.89 25df 63.4 121.7 122 0.0374 1.2206 211.96 26ce 96.2 72.84 5 0.034 0.0604 10.321 26ef 96.2 94.78 3 0.0442 0.0534 10.876 26cf 96.2 135.1 8 0.063 0.1018 19.91 26bg 93.1 28.19 39 0.0127 0.3902 45.2 26ac 96.5 79 55 0.0369 0.5512 59.815 26af 96.5 57.77 52 0.027 0.5207 61.448 26ac 96.5 86.39 60 0.0404 0.6014 63.852 26bd 92.3 13.95 199 0.0062 1.99 233.33 26ab 95.1 28.55 346 0.0131 3.46 275.13 26bc 94.8 111.9 286 0.0514 2.8605 310.38 26be 94.8 106.1 291 0.0487 2.9104 322.88 26dg 92.1 22.65 160 0.0101 1.6 334.2 26bf 94.8 56.19 294 0.0258 2.9401 355.43 27cd 263 169.4 96 0.2159 0.984 49.674 27ef 261 79.5 56 0.1004 0.5689 62.394 27ab 184 167.8 190 0.1499 1.9059 104.43 27df 262 42.43 156 0.0538 1.5609 116.83 27cf 262 134.8 252 0.1714 2.5258 143.37 27de 262 115 212 0.1457 2.125 187.9 27ce 262 55.35 308 0.0703 3.0808 197.91 28ab 115 74.89 48 0.0416 0.4818 31.51 28ac 114 42.56 151 0.0234 1.5102 133.72



GN

(1)

D (Mpc)

(2)

θ "

(3)

|∆∆∆∆v| km s-1

(4)

rp (Mpc)

(5)

rs (Mpc)

(6)

cr

(7) 28bc 114 39.91 199 0.022 1.9901 151.18 29cd 317 23.67 45 0.0363 0.4515 24.239 29bc 312 13.14 845 0.0199 8.45 378.64 30bd 46.5 127.8 41 0.0288 0.411 43.736 30ad 46.8 274.4 31 0.0622 0.3162 79.723 30ab 46.6 216.6 72 0.0489 0.7217 93.771 30bc 45.7 262.2 117 0.058 1.1714 119.83 30cd 45.9 253.8 158 0.0564 1.581 261.49 31ac 40.6 15.56 26 0.0031 0.26 36.13 31ab 41.1 52.55 129 0.0105 1.29 146.8 31bc 41.2 42.35 103 0.0085 1.03 170.17 32bc 121 169.5 141 0.099 1.4135 113.6 32ad 124 65.07 234 0.0392 2.3403 143.53 32bd 122 139.9 188 0.0828 1.8818 155.92 32ab 123 196.1 422 0.1172 4.2216 256.77 32cd 121 46.31 329 0.0273 3.2901 267.35 32ac 123 82.17 563 0.0488 5.6302 337.57 33cd 78 129 56 0.0487 0.5621 75.491 33bd 79.1 50.22 183 0.0193 1.8301 190.08 33ac 77 40.06 253 0.0149 2.53 293.5 33ad 76.7 94.81 197 0.0352 1.9703 298.82 33bd 78.9 85.54 239 0.0327 2.3902 314.44 34ad 89.1 32.9 180 0.0142 1.8001 193.26 34ac 91.9 51.63 395 0.023 3.9501 346.12 35bf 163 87.05 8 0.0689 0.1056 7.1679 35bc 163 70.68 19 0.056 0.1981 10.232 35cf 163 32.83 27 0.026 0.2712 25.133 35ad 159 68.77 121 0.0528 1.2112 92.74 35ab 161 41.98 419 0.0328 4.1901 221.97 35be 166 20.61 435 0.0165 4.35 283.55 35ac 161 38.91 438 0.0304 4.3801 293.17 35bd 161 110 540 0.0857 5.4007 309 35ce 166 90.59 416 0.0727 4.1606 364.84



GN

(1)

D (Mpc)

(2)

θ "

(3)

|∆∆∆∆v| km s-1

(4)

rp (Mpc)

(5)

rs (Mpc)

(6)

cr

(7) 37ab 67.4 92.7 4 0.0303 0.0502 2.6471 37ae 65.5 184.3 382 0.0585 3.8204 257.11 37de 62.9 91.22 156 0.0278 1.5602 259.3 37ad 64.8 107.5 538 0.0337 5.3801 352.45 37be 65.5 145.1 378 0.0461 3.7803 389.45 37ac 70.5 38.53 612 0.0132 6.12 390.29 38ac 87.7 159.2 10 0.0676 0.1207 10.141 38ab 87.5 146.2 21 0.062 0.219 14.052 38bc 87.5 13.41 31 0.0057 0.3101 19.647 39bd 211 41.34 128 0.0423 1.2807 101.04 39ab 211 2686 57 2.7528 2.8112 172.24 39ad 211 2708 71 2.7663 2.856 186.11 39cd 209 58.78 381 0.0594 3.8105 306.03 39ac 209 2672 452 2.7056 5.2678 327.25 39bc 209 18.15 509 0.0184 5.09 379.11 40ae 66.3 42.58 3 0.0137 0.033 2.6473 40bc 68.7 36.75 48 0.0122 0.4802 40.823 40ad 65.6 53.79 136 0.0171 1.3601 95.905 40ab 67.4 65.43 214 0.0214 2.1401 146.99 40de 65.6 73.55 133 0.0234 1.3302 156.99 40ac 67.6 37.52 262 0.0123 2.62 170.52 40be 67.3 30.59 217 0.01 2.17 245.18 40ce 67.6 34.24 265 0.0112 2.65 274.44 40bd 66.7 103.9 350 0.0336 3.5002 330.86 40cd 66.9 88.08 398 0.0286 3.9801 349.61 43df 96.3 129.7 6 0.0606 0.0852 11.254 43ab 101 197.2 76 0.0968 0.7661 60.148 43bc 100 118.6 171 0.0575 1.711 146.73 43ac 100 193.9 247 0.0943 2.4718 209.48 43cd 97.7 70.11 286 0.0332 2.8602 307.58 43ce 97.8 63.56 280 0.0301 2.8002 311.18 44ac 12.6 641.1 75 0.039 0.751 108.92 44ab 13.4 343.9 85 0.0223 0.8503 112.64



GN

(1)

D (Mpc)

(2)

θ "

(3)

|∆∆∆∆v| km s-1

(4)

rp (Mpc)

(5)

rs (Mpc)

(6)

cr

(7) 44bc 13 978.9 160 0.0616 1.6012 276.29 44bd 14.8 520.1 201 0.0373 2.0103 308.34 44ad 14.4 294 286 0.0205 2.8601 375.36 45ac 218 173.5 12 0.1834 0.2191 6.9907 45ab 220 111.9 384 0.1193 3.8419 106.37 45bc 220 78.49 396 0.0837 3.9609 226.42 46cd 78 102.4 203 0.0387 2.0304 316.03 47bd 94.8 75.45 16 0.0347 0.1637 13.081 47ac 95.6 136.3 52 0.0631 0.5238 37.129 47bc 95.1 90.72 42 0.0418 0.4221 38.393 47ab 95.3 52.07 94 0.0241 0.9403 55.209 47cd 95 23.72 58 0.0109 0.5801 60.481 47ad 95.3 116.6 110 0.0538 1.1013 70.463 48cd 43.3 10.8 20 0.0223 0.3108 44.097 49bc 99.3 14.88 4 0.0072 0.0406 4.2988 49ab 99.3 47.16 9 0.0227 0.0928 7.8672 49ac 99.3 32.53 13 0.0157 0.1309 11.971 49ad 99.7 27.7 71 0.0134 0.7101 66.668 49bd 99.7 34.13 80 0.0165 0.8002 87.295 49cd 99.7 21.9 84 0.0106 0.8401 101.14 50bc 413 37.98 228 0.076 2.2813 110.74 50ae 418 24.71 220 0.05 2.2006 115.85 50ce 415 41.35 252 0.0832 2.5214 160.15 50ac 416 23.94 472 0.0483 4.7202 230.42 50be 414 10.97 480 0.022 4.8001 251.18 50ad 422 23.65 676 0.0484 6.7602 292.05 50ab 415 16.69 700 0.0336 7.0001 293.48 53ab 62.1 242.4 95 0.073 0.9528 53.419 53bc 61.1 43.23 106 0.0128 1.0601 105.12 53ac 61.6 199.4 201 0.0595 2.0109 120.16 54bc 14.2 35.74 8 0.0025 0.08 125.29 54ab 14 17.37 15 0.0012 0.15 135.4 54ac 14.1 18.47 23 0.0013 0.23 208.81



GN

(1)

D (Mpc)

(2)

θ "

(3)

|∆∆∆∆v| km s-1

(4)

rp (Mpc)

(5)

rs (Mpc)

(6)

cr

(7) 55ab 158 32.76 130 0.025 1.3002 83.045 55bc 156 16.04 210 0.0121 2.1 130.35 55ad 159 21.39 250 0.0165 2.5001 158.92 55ac 157 17.1 340 0.013 3.4 166.17 55bd 159 53.81 380 0.0414 3.8002 333.87 55cd 158 37.82 590 0.0289 5.9001 364.51 56be 79.2 80.7 5 0.031 0.0588 6.3235 56ad 83 105.1 101 0.0423 1.0109 105.28 56ac 81.8 93.13 135 0.0369 1.3505 113.58 56bc 80.1 35.56 191 0.0138 1.91 167.19 56ce 80.2 46.72 186 0.0182 1.8601 177.29 56cd 82.3 12.69 236 0.0051 2.36 228.54 56ab 80.8 65.82 326 0.0258 3.2601 304.66 56ae 80.8 125.9 321 0.0493 3.2104 328.68 57de 89.8 166.5 15 0.0725 0.1666 13.118 57be 90.1 96.58 30 0.0422 0.3029 18.95 57bd 90 180.6 45 0.0787 0.4568 26.056 57bc 90.5 170.1 59 0.0746 0.5947 28.366 57ce 90.4 190.4 89 0.0834 0.8939 55.411 57cd 90.3 63.21 104 0.0277 1.0404 58.849 57ad 88.5 25.38 250 0.0109 2.5 122.63 57ab 88.7 174 295 0.0748 2.9509 124.66 57ae 88.6 174 265 0.0747 2.6511 140.72 57fg 95.1 332.4 178 0.1531 1.7866 148.4 57ac 89 37.83 354 0.0163 3.54 148.63 57cg 92.5 196.2 335 0.0879 3.3512 219.75 57bg 92.2 43.35 394 0.0194 3.94 260.85 57cf 93.4 139.7 513 0.0632 5.1304 286.61 57bf 93.1 300.8 572 0.1357 5.7216 322.26 57dg 92 193.5 439 0.0862 4.3908 371.55 57ag 90.7 192.4 689 0.0846 6.8905 383.71 58ac 61.2 280.9 35 0.0833 0.3598 21.713 58ce 60.8 334.9 51 0.0986 0.5195 39.815



GN

(1)

D (Mpc)

(2)

θ "

(3)

|∆∆∆∆v| km s-1

(4)

rp (Mpc)

(5)

rs (Mpc)

(6)

cr

(7) 58ae 61 393.1 86 0.1161 0.8678 61.41 58ad 62 274.2 132 0.0824 1.3226 78.153 58cd 61.9 252.4 167 0.0757 1.6717 105.55 58bd 63.9 406.6 233 0.1258 2.3334 120.05 58de 61.6 119.8 218 0.0358 2.1803 162.71 58ab 63.2 190.8 365 0.0584 3.6505 181 58bc 63 471.2 400 0.1439 4.0026 209.74 58be 62.8 511.9 451 0.1557 4.5127 271.12 59bd 38.9 162.1 42 0.0305 0.4211 77.185 59ab 40.1 114.9 201 0.0223 2.0101 326.05 59ac 42.3 107.7 238 0.0221 2.3801 386.9 60bd 183 135.8 18 0.1205 0.2166 14.505 60ac 191 36.67 270 0.034 2.7002 118.87 60ab 187 120.7 689 0.1092 6.8909 314.4 60ad 187 26.4 707 0.0239 7.07 335.7 61cd 39.7 88.79 24 0.0171 0.2406 26.605 61ac 38.7 167.3 172 0.0314 1.7203 129.58 61ad 38.8 154.3 196 0.029 1.9602 171.12 62ac 43.6 65.3 4 0.0138 0.0423 3.3546 62ad 42.4 193.2 232 0.0397 2.3203 184.29 62cd 42.4 221.1 236 0.0454 2.3604 322.15 63bc 94 103.9 114 0.0473 1.141 54.282 63bd 92.4 56.57 205 0.0253 2.0502 119.16 63cd 93 113.2 319 0.051 3.1904 300.87 64ab 107 52.33 127 0.027 1.2703 56.675 64bd 109 16.44 377 0.0087 3.77 284.46 64ad 108 68.61 504 0.0361 5.0401 345.59 65ac 142 87.87 138 0.0604 1.3813 41.737 65ce 143 28.1 162 0.0195 1.6201 1010.1 65ae 143 102.6 300 0.0709 3.0008 121.67 65ad 139 17.19 372 0.0116 3.72 137.32 65ab 144 81.47 595 0.0569 5.9503 173.05 65be 146 22.15 295 0.0156 2.95 184.34



GN

(1)

D (Mpc)

(2)

θ "

(3)

|∆∆∆∆v| km s-1

(4)

rp (Mpc)

(5)

rs (Mpc)

(6)

cr

(7) 65bc 145 28.18 457 0.0198 4.57 187.02 65cd 140 77.78 510 0.0527 5.1003 297.55 66cd 208 14.96 49 0.0151 0.4902 43.001 66ac 207 29.74 113 0.0299 1.1304 58.664 66ad 208 42.41 162 0.0427 1.6206 94.613 66ab 211 17.47 784 0.0178 7.84 363.97 67ac 73.5 55.95 168 0.0199 1.6801 186.08 67ad 71.7 35.51 191 0.0123 1.91 190.68 67bc 75.4 200.4 214 0.0732 2.1413 249.26 67ab 74.5 204.1 382 0.0737 3.8207 351.12 68de 24 283.5 7 0.033 0.0774 13.431 68ce 23.6 542.1 88 0.0619 0.8822 84.497 68cd 23.6 288.1 95 0.0329 0.9506 88.278 68ac 22.4 294.6 151 0.0319 1.5103 101.99 68bd 25.2 252.3 227 0.0308 2.2702 173.93 68bc 24.7 226.2 322 0.0271 3.2201 181.62 68be 25.2 392.7 234 0.0479 2.3405 183.93 68ad 22.9 295.1 246 0.0327 2.4602 242.85 68ae 22.8 381.1 239 0.0421 2.3904 243.84 68ab 24 70.31 473 0.0082 4.73 276.72 69ab 87.8 107.1 149 0.0456 1.4907 97.368 69bc 86.3 92.21 161 0.0385 1.6105 153.61 69ac 87 37.59 310 0.0158 3.1 208.32 69ad 90 20.52 293 0.009 2.93 213.74 70ab 82.2 107.5 40 0.0428 0.4023 29.364 70eg 191 82.65 107 0.0764 1.0727 60.654 70ef 192 35.57 126 0.0331 1.2604 69.78 70bc 81.4 130.4 119 0.0514 1.1911 93.032 70dg 189 134 164 0.1229 1.6446 106.58 70de 190 103.9 271 0.0956 2.7117 131.57 70ac 81.6 142.4 159 0.0563 1.591 137.15 70fg 191 54.27 233 0.0503 2.3305 180.9 70df 190 92.87 397 0.0857 3.9709 251.19



GN

(1)

D (Mpc)

(2)

θ "

(3)

|∆∆∆∆v| km s-1

(4)

rp (Mpc)

(5)

rs (Mpc)

(6)

cr

(7) 71ab 93.3 111 15 0.0502 0.1582 9.1178 72ad 125 79.09 52 0.048 0.5222 45.4 72ab 124 62.76 150 0.0378 1.5005 114.05 72bd 125 18 202 0.0109 2.02 153.93 74ac 123 21.5 11 0.0128 0.1107 5.3483 74ab 122 22.03 145 0.013 1.4501 62.451 74bc 122 41.46 156 0.0245 1.5602 99.905 74de 116 107.1 192 0.0601 1.9209 252.21 74ad 120 110 574 0.0638 5.7404 300 74bd 119 110.1 429 0.0635 4.2905 305.47 75ce 123 66.25 8 0.0395 0.0892 8.949 75de 123 44.81 34 0.0267 0.3411 37.03 75cd 123 27.37 42 0.0163 0.4203 44.458 75bc 123 130.5 64 0.0775 0.6447 58.628 75be 123 71.62 72 0.0426 0.7213 67.082 75bd 123 103.8 106 0.0617 1.0618 103.72 75ad 124 99.94 204 0.0602 2.0409 129.82 75ae 124 65.31 238 0.0393 2.3803 146.62 75ac 124 126.3 246 0.076 2.4612 149.35 75ab 124 8.639 310 0.0052 3.1 179.58 75af 128 19.34 542 0.012 5.42 361.32 76ab 100 155.7 52 0.0756 0.5255 35.372 76df 102 180.4 66 0.089 0.666 48.79 76ad 101 111.1 96 0.0544 0.9615 69.372 76bd 101 189.5 148 0.0925 1.4829 88.61 76bg 99.2 77.44 159 0.0372 1.5904 98.694 76ef 103 184.6 112 0.0919 1.1238 116.11 76af 101 158.4 162 0.0778 1.6219 137.79 76bf 101 18.92 214 0.0093 2.14 146.13 76de 102 148.7 178 0.0738 1.7815 151.38 76ag 99.5 231.1 211 0.1114 2.1129 159.58 76dg 100 244.9 307 0.1186 3.0723 203.2 76ce 105 198 335 0.1007 3.3515 229.7



GN

(1)

D (Mpc)

(2)

θ "

(3)

|∆∆∆∆v| km s-1

(4)

rp (Mpc)

(5)

rs (Mpc)

(6)

cr

(7) 76be 102 178.3 326 0.0878 3.2612 255.51 76cf 104 91.12 447 0.0461 4.4702 271.38 76cd 104 120.1 513 0.0606 5.1304 276.38 76ae 102 40.79 274 0.0201 2.7401 277.08 76fg 100 72.89 373 0.0354 3.7302 286.28 76bc 103 108.3 661 0.0542 6.6102 337.99 76ac 104 159.7 609 0.0801 6.0905 365.07 79bd 44.7 60.52 57 0.0131 0.5702 37.548 79ab 43.7 36.36 154 0.0077 1.54 71.961 79ac 42.2 27.34 146 0.0056 1.46 86.966 79ad 44 28.92 211 0.0062 2.11 147.25 79bc 43 23.91 300 0.005 3 170.03 79cd 43.2 56.24 357 0.0118 3.57 337.68 80bc 95.7 96.75 34 0.0449 0.3429 40.237 80ad 90.4 57.91 145 0.0254 1.4502 163.52 81bc 151 19.81 100 0.0145 1.0001 79.464 81cd 150 9.843 96 0.0072 0.96 79.562 81bd 151 25.51 196 0.0186 1.9601 175.77 81ad 148 29.35 278 0.0211 2.7801 262.83 81ac 149 39.19 374 0.0282 3.7401 311.36 82bc 103 157.1 352 0.0782 3.5209 210.52 82ad 114 147.3 508 0.0816 5.0807 312.25 82ab 108 71.41 730 0.0374 7.3001 351.75 83ae 156 39.51 0 0.0298 0.0298 3.7299 83ad 155 74.91 60 0.0564 0.6026 71.244 83bc 165 74.27 78 0.0593 0.7823 71.962 83de 155 67.6 60 0.0509 0.6022 132.85 84ab 166 76.53 100 0.0616 1.0019 48.273 84ad 167 90.98 146 0.0737 1.4619 80.973 84bc 165 114.2 201 0.091 2.0121 125.59 84ac 165 38.76 301 0.031 3.0102 140.83 84de 169 103.3 150 0.0844 1.5024 171.15 84ae 168 14.74 296 0.012 2.96 175.86



GN

(1)

D (Mpc)

(2)

θ "

(3)

|∆∆∆∆v| km s-1

(4)

rp (Mpc)

(5)

rs (Mpc)

(6)

cr

(7) 84bd 167 37.36 246 0.0302 2.4602 193.71 84cd 166 129.5 447 0.1041 4.4712 335.66 84be 168 84.9 396 0.0689 3.9606 345.03 85cd 119 42.28 12 0.0244 0.1225 16.815 85bc 120 47.24 210 0.0275 2.1002 191.58 85bd 120 44.81 222 0.0261 2.2202 197.66 86ab 61.9 132 22 0.0396 0.2235 17.82 86ad 60.5 228.9 258 0.067 2.5809 242.69 86bd 60.6 97 280 0.0285 2.8001 291.94 87bc 89.5 89.11 52 0.0386 0.5214 40.544 87ac 88.1 75.11 226 0.0321 2.2602 160.88 87ab 88.3 61.48 278 0.0263 2.7801 187.26 88ad 60.3 460.9 1 0.1347 0.1351 9.8644 88ab 60.2 153.6 23 0.0448 0.2343 13.34 88bd 60.2 314.3 22 0.0917 0.2383 17.507 88ac 60.6 261.7 50 0.0768 0.5059 31.776 88cd 60.6 218.5 51 0.0641 0.514 42.944 88bc 60.5 108.2 73 0.0317 0.7307 46.135 89ad 88.5 115.4 7 0.0495 0.0857 7.1209 89ac 88.6 110.8 22 0.0476 0.2251 16.002 89cd 88.6 34.56 15 0.0148 0.1507 19.984 89bc 89.3 180 113 0.0779 1.1327 79.721 89ab 89.2 287.8 135 0.1244 1.3557 86.687 89bd 89.2 173.7 128 0.0751 1.2822 140.66 90ab 25.5 442 50 0.0546 0.503 43.315 90cd 27.4 79.67 82 0.0106 0.8201 73.667 90ac 26.4 376.1 121 0.048 1.211 107.1 90ad 26.8 449.8 203 0.0583 2.0308 147.98 90bc 26.1 89.3 171 0.0113 1.71 189.57 90bd 26.5 34.07 253 0.0044 2.53 221.2 91cd 72.6 99.24 124 0.0349 1.2405 111.78 91ad 70.1 34.67 363 0.0118 3.63 214.17 91ac 70.8 131.1 487 0.045 4.8702 244.8



GN

(1)

D (Mpc)

(2)

θ "

(3)

|∆∆∆∆v| km s-1

(4)

rp (Mpc)

(5)

rs (Mpc)

(6)

cr

(7) 91bc 72.6 7016 123 2.4673 2.7568 246.4 91ab 70.1 6919 364 2.3514 4.333 254.29 91bd 72 6951 1 2.4234 2.4234 294 92de 66.1 95.36 31 0.0306 0.3115 17.373 92cd 67 93.41 134 0.0303 1.3403 51.331 92ce 66.8 182.3 165 0.059 1.6511 73.369 92bc 62.7 74.06 990 0.0225 9.9 348.6 92bd 62 20.67 856 0.0062 8.56 359.27 93ac 51.4 180.7 8 0.045 0.0918 6.2849 93ad 51.6 394.7 33 0.0986 0.3444 26.811 93cd 51.5 497.6 41 0.1242 0.4284 42.303 93ab 49.1 288.9 468 0.0687 4.6805 336.88 94ab 120 32.87 66 0.0191 0.6603 28.522 94ac 121 136 80 0.0796 0.804 36.154 94bc 120 168.8 146 0.0985 1.4633 89.468 94ce 122 74 130 0.0437 1.3007 107.37 94ae 121 73.41 210 0.0432 2.1004 111.09 94df 130 109.3 89 0.0686 0.8926 119.04 94be 121 105.2 276 0.0617 2.7607 211.92 94dg 131 150 191 0.0953 1.9124 256.62 95bc 116 49.26 75 0.0277 0.7505 44.653 95ab 118 74.03 251 0.0422 2.5104 121.28 95ac 117 25.2 326 0.0143 3.26 146.85 95ad 121 57.47 462 0.0337 4.6201 243.85 96ac 87.3 32.85 55 0.0139 0.5502 30.824 96ab 86.6 140.2 82 0.0588 0.8221 40.631 96bc 86.8 119.2 137 0.0502 1.3709 122.69 96ad 88.4 62.7 277 0.0268 2.7701 177.53 96cd 88.6 59.36 222 0.0255 2.2201 339.27 97ab 69.3 229.4 30 0.077 0.3097 17.937 97ae 67.4 86.47 331 0.0283 3.3101 206.52 97cd 61.2 155.3 244 0.046 2.4404 232.16 97be 67.6 299.8 361 0.0982 3.6113 340.39



GN

(1)

D (Mpc)

(2)

θ "

(3)

|∆∆∆∆v| km s-1

(4)

rp (Mpc)

(5)

rs (Mpc)

(6)

cr

(7) 97de 64.1 117 340 0.0363 3.4002 346.86 98ab 79.1 38.84 104 0.0149 1.0401 54.471 98bc 80.5 74.95 186 0.0292 1.8602 186.06 98ac 80 108.9 290 0.0422 2.9003 191.78 99ad 86.7 105.8 62 0.0445 0.6216 48.34 99ab 87.8 133 141 0.0565 1.4111 71.549 99be 89.3 132.2 161 0.0572 1.611 111.78 99bd 87.4 111.4 203 0.0472 2.0305 153.75 99ae 88.6 80.89 302 0.0347 3.0202 214.74 99ac 84.6 99.38 489 0.0407 4.8902 295.12 99bc 85.3 38.38 630 0.0159 6.3 372.4 100ab 52.8 88.38 47 0.0226 0.4705 44.598 100ac 53.8 152.9 161 0.0399 1.6105 158.17 100bc 53.6 215.8 208 0.056 2.0808 265.66



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Galaxy Pairs and Star Formation Activity in Hickson Compact Groups

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