Globular-Cluster Catalog
Arp H.C.
<Stars and Stellar Systems, Vol. 5, gen. ed. G.P. Kuiper, eds. A. Blaauw and M . Schmidt, Chapter 19, p. 410. (1965)>
Description:
This catalog is the Globular Cluster Catalog published by Halton C. Arp in 1965 as part of a review paper on globular Clusters. The review focused on the slightly more than a hundred roughly spherical star clusters that have integrated color indices between B-V = 0.6 an 0.8 mag and intrinsic magnitudes between Mbol = -4 and -10 mag. They are distributed about the center of the galaxy. Such clusters contain stars that are very old and metal poor. The catalog improves upon the earlier publication by Mrs. Hogg (1959). An estimate of the completeness of the catalog is 98 percent complete for galactic latitudes above b(II)=8 degrees and 94 percent complete for low latitudes for concentration classes less than XI. This catalog lists for all 119 clusters: the NGC number, or other ID, the name, the position in equatorial and galactic coordinates, the concentration class, galactic absorption, diameter at 0.9, magnitude of 25-st brightest star, distance modulus, galactic radius, x, y, and z positions, total brightness, apparent and intrinsic colors, spectral type and radial velocity.
File Summary:
| FileName | Lrecl | Size | Records | Explanations |
| ReadMe | 80 | 9KB | This file | |
| catalog.dat | 136 | 5KB | 119 | *Catalog Data |
Note on Catalog.dat:
NGC 2158 was dropped from Mrs. Hogg's list, because although Arp and McCuffey (1962) have shown this to be a transitional cluster in many respects, it is nevertheless similar instellar content to NCG 7789 and NGC 752, which have been traditionally classified as galactic clusters. Also dropped was the socalled ''Russian cluster'' because under high resolution it proves to be a cluster of galaxies. Added was a faint, sparse globular cluster at 19h30m and -30d, a plate of which was found in Baade's files, and a globular cluster at low lattitudes, NGC 6749, pictured in Setteducati and Weaver (1962), as well as a faint, distant cluster discovered by Arp and van den Bergh (1960).
Byte-by-byte Description of file: catalog.dat
| Bytes | Format | Units | Label | Explanations |
| 1-6 | A6 | ID | *NGC number or other | |
| 7 | A1 | n_ID | *[ 5] note | |
| 9-18 | A10 | name | cluster name | |
| 20-21 | I2 | Con_Cl | *?Concentration Class | |
| 22 | A1 | u_Con_Cl | uncertainty indicator Concentration Class | |
| 25-26 | I2 | h | RAh | Right Ascension hours (1950.0) |
| 28-31 | F4.1 | min | RAm | Right Ascension minutes (1950.0) |
| 32 | A1 | DE- | Declination sign (1950) | |
| 33-34 | I2 | deg | DEd | Declination degrees (1950) |
| 36-37 | I2 | arcmin | DEm | Declination arc minutes (1950) |
| 39-41 | I3 | deg | GLON | Galactic Longitude l II |
| 42 | A1 | n_GLON | note to GLON | |
| 45-47 | I3 | deg | GLAT | Galactic Lattitude b II |
| 48-52 | F5.2 | ABS_LAW | Galactic Absorption from formula 0.24 csc b | |
| 54-57 | F4.2 | mag | A(B) | ? Kron-Mayal case II absorption law |
| 58-61 | F4.1 | arcsec | D(0.9) | ?Diameter (containing 0.9 of the light) |
| 62 | A1 | u_D(0.9) | uncertainty indicator Diameter | |
| 64-68 | F5.2 | mag | Bmean | *?Mean B mag of 25 brightest stars |
| 70-74 | F5.2 | Dmod | *?distance modulus (m-M)app from Bmean | |
| 76 | A1 | n_Dmod | *note to Dmod | |
| 78-82 | F5.1 | kpc | r | ?galactic radius from Dmod and ABS_LAW, Fig.7 |
| 85-89 | F5.1 | kpc | x | *?Sun centered galactic X-coordinate |
| 92-96 | F5.1 | kpc | y | *?galactic y-coordinate in direction rotation |
| 99-103 | F5.1 | kpc | z | *?height above galactic plane |
| 106-110 | F5.2 | mag | Btot | *?apparent integrated B brightness |
| 112-115 | F4.2 | mag | B-V | ?apparent color from Kron and Mayal (1960) |
| 117-120 | F4.1 | mag | M(B) | *?absolute magnitudes from Btot |
| 122-125 | F4.2 | mag | (B-V)o | ?intrinsic color using E(B-V) = 0.06 csc b |
| 127-128 | A2 | Sp | spectral type from Kron and Mayal (1960) | |
| 130 | A1 | n_Sp | *[ :346]note on Spectral type | |
| 132-135 | I4 | km/s | RV | ?cluster radial velocity |
Note on ID:
102 clobular clusters have NGC designations 2 are listed in the Index catalogues
Note on Con_Cl:
The roman numerals have been replaced by arabic numerals.
Note on Bmean:
The apparent B magnitudes of the mean of the 25 brightest stars. Older photographic magnitudes have all been corrected using the photometric recalibration of the Selected Areas and the color index correction to the B system by Arp. Bmean can be used to estimate the distance of the cluster based on a mean intrinsic magnitude M(B) = -0.8 mag. This is used to derive the Dmod value.
Note on n_ID, n_Sp,n_Dmod:
Unmarked entries of Spectral Type are from Kron and Mayal (1960)
: uncertain value
1 from V(hor br), table 6 in reference
2 adjusted to RR Lyrae distance scale via figure 7 in reference
3 Spectral type from Kinman (1959b).
4 Kinman (1959b) gives F2
5 Arp-Van den Bergh
6 Kinman (1959b) gives F3
Note on Btot, M(B):
Apparent magnitudes measured by kron and Mayal (1960) were transformed into the Johnson V system, transformed color indices were applied to derive Btot. Absolute magnitudes M(B) were found for the clusters that have distances using the csc reddening law.
Earlier measures of integrated globular cluster magnitudes by Christie (Hogg 1959) can be compared to the Kron-Mayal measures. Transforming both measures to the B system, it can be shown that they correlate well. The data for 12 additional clusters based on the Christie measures were included.
Note on x,y,z:
The coordinate system x,y, and z is centered on the Sun, with x directed toward the galaxy center, y in the direction of the rotation, and z perpendicular to the plane. In order to get a coordinate sytem with its center at the center of the galaxy it is only neccesary to substract Ro, the distance between the Sun and the center of the galaxy, from x.
Other parameters:
Cluster mass. Only for 2 clusters the mass was determined based on the intermal kinematics. These are M92 (110,000 Msun) and 47 Tuc (2.5 to 6 million Msun).
Remarks and Modifications:
Arp's Globular Cluster Catalogue has been made machine-readable by Dr. N.P.M. Kuin at the ADC since catalog was requested frequently and the original version submitted by Dr. G. Share only contained ID and positions.
References:
H. C. Arp, in Galactic Structure, ed. A. Blaauw and M. Schmidt, 1965, University of Chicago Press, p. 401.
Arp, H.C. and Van den Bergh S. 1960 PASP 72, 48
Arp, H.C. and McCuffey, J. 1962 ApJ 136, 51
Hogg, Helen Sawyer 1959 Hdb. d. Phys., ed. S. Fluegge (Berlin: Springer Verlag) 53, 129
Kinman T.D. 1959b MNRAS 119, 538
Kron G.E. and Mayal N.U. 1960 AJ 65, 581
Setteducati, A.F. and Weaver, H.F. 1962 Newly Found Star Clusters, Vol. 1 (Berkeley, University of California, Radio Astronomy Laboratory)
(End) N.P.M. Kuin 24-Apr-1996