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HIGH SURFACE BRIGHTNESS GALAXIES

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DEFINITION, STAR FORMATION, BASIC DATA

The small group of High Surface Brightness Galaxies (HSBGs) offers a large field of studying different properties of galaxies in general. HSBGs have been registered amongst Seyfert Galaxies, X-ray sources, high luminosity objects and many Infra Red sources.

Holmberg (1952), while making detailed surface photometry of ca. 100 bright galaxies, defined B≤13.6 [mag/sq.min] as a border splitting the high surface brightness objects from the normal one. Arakelian (1974) found that many physical characteristics of galaxies correlated with their surface brightness. Amongst them are spectral emission lines, radio emission, colours, etc.

Using Holmberg’s criteria, Arakelian (1975) determined the surface brightness of all galaxies to the north of Delta ≤ -3 deg, that have photographic magnitudes in CGCG (Zwicky et al., 1960 - 1968) and diameters in MCG (Vorontsov-Vel'jaminov et al., 1962 -1968). The basic relation is

(1) B = m_Zw+ 2.5Lg(Pi/4*D*d) - 0.22cosec(b^II) [m/sq.sec]

B_Akn are transfomed to Holmberg's one using the simple relations based on the least square fit for ca. 100 common objects:

(2) B_Akn = B + 0.22D/d + 0.73

Thus Arakelian (1975) differentiated 591 objects with HSB in the northern hemispere. Kojoian et al.1(981) determined accurate optical positions for these objects.

Using Arakelian's criteria, Petrov (1986) presented a list of 47 new galaxies with HSB (NHSBG) from the UGCG. Rem.: Nilson's diameters are systematically larger (i.e., lower SB). In this list there are 19 Zwicky (1971) compact galaxies (40%) and 2 SyGs - IZw 1 and IIZw 136.

As there were some speculations (e. g. Karachentsev et al, 1986) the HSBG simple is the most compact part of the normal galaxies. We tried to show they were quite a homogenous group, too. To prove that we reduced Arakelian's system of surface brightness to the standard isophote 25 mag/sq.sec. The reduction procedure included conversion of MCG-diameters to D₂₅ (Paturel, 1977).

(3) D₂₅ = D₂₅ (al,del,T,b^II)

The transformation of Zwicky magnitudes m_Zw to corrected Holmberg magnitudes m_Holm is:

(4) m_corr = m_Holm (m_Zw,D,al,del,T, b^II,R)

i.e. (5) SB₂₅ = m_corr + 2.5Lg(Pi/4*D₂₅* D₂₅) + 8,89 [m/sqr.sec]

and (6) SB₂₅= (0.882+-0.077) B_Akn + (2.322+-1.675)

COMPARISON OF THE BASIC PROPERTIES OF THE N ORMAL AND HIGH SURFACE BRIGHTNESS GALAXIES

What are "normal" galaxies? Up to now most astronomers have used the evaluations made by E. Holmberg or G. de Vaucouleurs many years ago based usually on small samples of galaxies. We construct a basic picture of normal galaxies using the homogenous sample of 1939 objects not belonging to any group of galaxies such as SyGs, MrkGs, AknGs, DDO galaxies, etc. up to 14.5 magnitude from the Center for Astrophysics, USA.

Student's "t- test" and Fisher's "f-test" have been used to check the statistical significances that the HSBGs are a homogenous group with different average parameters from the ones of the normal galaxies. The main differences are:

· The normal galaxies have lower luminosities and larger diameters than HSB ones;

· The HSBGs are a sample of the normal galaxies with on the average higher surface brightness, higher luminosities and smaller diameters;

· The HSBG are more distant on the average;

· IR luminosities are more common for the more compact objects;

· Amongst CfA normal galaxies there are new 93 objects with high

· We could expect increasing or constant SFR than decreasing one.

SURFACE BRIGHTNESS OF EMISSION-LINE GALAXIES

It is shown that the relative number of emission line galaxies significantly decreases with the decrease of the mean surface brightness. Similar phenomenon takes place when Zwicky compact galaxies are considered. These results are interpreted as due to the fact, that the duration of emission line phase is in correlation with the surface brightness of galaxies.

MEAN SURFACE BRIGHTNESS OF ISOLATED AND DOUBLE GALAXIES

The mean surface brightness of isolated galaxies and galaxies that are members of systems are compared in order to obtain information pertaining to the different conditions under which these galaxies were formed. The comparison of the spiral galaxies in the Catalog of Isolated Galaxies (Karachentseva, 1973) and the Catalog of Isolated Pairs (Karachentsev, 1972) reveals that the difference between the mean values of mean surface brightness of the corresponding galaxies equals 0.35. The mean surface brightness of the components of pairs are greater than those of isolated galaxies, indicating the dependence of the former on the separation of the components. The mean value of the mean surface brightness of the components of the pairs reaches that of the isolated galaxies at a distance r = 225 kpc, where the mutual influence of the components of pairs is greatly reduced.

OUR RESEARCH ON HIGH SURFACE BRIGHTNESS GALAXIES

Click here for more details about high surface brightness galaxies.

PUBLISHED PAPERS

1. MINEVA V. A., PETROV G. T., KOVACHEV B.J. , C. r. Acad.Sci.Bulg., v. 34, 1629-1632, 1981 “Spectrophotometric study of high surface brightness galaxies. I. Arakelian 144”
2. MINEVA V. A., PETROV G. T., GOLEV V. K., TSVETANOV Z. I. , Pis'ma AJ, v. 8, 210-213, 1982 (in Russian) “Spectrophotometry of the nucleus of the galaxy Arakelian 144”
3. PETROV G. T., MINEVA V. A., GOLEV V. K., TSVETANOV Z. I. , Astr. Tsirc. No.1202, 4-5,1982 (in Russian) “Spectrophotometry of the nucleus of the galaxy Arakelian 583”
4. PETROV G. T., MINEVA V. A., GOLEV V. K. , C. r. Acad. Sci. Bulg., v. 35, 137-140, 1982 “Spectrophotometric study of galaxies with high surface brightness. II. Arakelian 583”
5. GOLEV V. K., PETROV G. T., TSVETANOV Z. I., Astr. Tsirc. No. 1292, 1-3, 1983 (in Russian)
   “The Hubble diagram and the luminosity distribution of Arakelian galaxies”
6. GOLEV V. K., TSVETANOV Z. I., PETROV G. T. , C. r. Acad. Sci. Bulg., v. 37, 15-18, 1984
   “On the space density of the Arakelian galaxies”
7. MARKOV KH. S., ZHEKOV S. A., PETROV G. T., TSVETANOV Z. , Astr. Tsirc. No. 1378, 1-3, 1985 (in Russian)
   “Spectra of galaxies obtained with "ROZHEN" 2-m telescope of the Bulgarian Academy of Sciences”
8. GOLEV V. K., TSVETANOV Z. I., PETROV G. T. , Astr. Invest.(Bulg. AS), v. 4, 95-105, 1985 (in Russian)
   “Results of a spectroscopic investigation of some Arakelian galaxies”
9. MARKOV KH. S., GOLEV V. K., TSVETANOV Z., PETROV G. T. , Astr. Invest. (Bulg.AS), v. 4, 106-110,1985 (in Russian)
   “Morphological investigations of galaxies with high surface brightness. II. Arakelian 26, 27, 28, 31, 32 and 79”
10. PETROV G. T. , Ap & Spa. Sci., v. 124, 407-433, 1986
    “New galaxies with high surface brightness in the Nilson system”
11. PETROV G. T. , Ap & Spa. Sci., v. 151, 169-175, 1989
    “Star burst activity in High Surface Brightness Galaxies”
12. PETROV G.T., MINEVA V.A., C. r. Acad. Sci. Bulg., v. 41, No. 11, 1988
    “Masses and rotational momenta of Arakelian galaxies”
13. PETROV G.,YANKULOVA I., C. r. Acad. Sci. Bulg., v. 43, No. 11,1990
    “Surface brightness and Star formation in Arakelian galaxies”
14. PETROV G., Astr. Invest. (Bulg. AS), v. 6, p. 3-11, 1991
    “CCD-spectra of the galaxy Arakelian 144”
15. PETROV G., YANKULOVA I. , C. r. Acad. Sci. Bulg., v. 44, No. 4,1991
    “Evidences for high star formation activity in the Arakelian galaxies”
16. PETROV G., C. r. Acad. Sci. Bulg., v. 44, No. 5,1991
    “Statistical comparison of the basic parameters of high surface brightness and normal galaxies”
17. JANKULOVA I., GOLEV V., PETROV G. , Astrofiz. Issled. (Izv. SAO), v. 35, 60-75, 1993
    “An evidence for enchanced star formation rate in IRAS-Detected Arakelian galaxies”
18. SLAVCHEVA L., MIHOV B., PETROV G., BACHEV R., IAU Symp. 194, p. 87, 1999
    “Spectrophotometry of selected AGN. Seyfert galaxy Arakelian 564”
19. PETROV G., SLAVCHEVA L., BACHEV R., MIHOV B., IAU Symp. 194, p. 84, 1999.
    “Surface photometry of barred AGN. Arakelian 564”

Created by G. T. Petrov