Yuri N. Efremov
Birth: May 11, 1937
married, one son
Degrees: Ph. D. (Cand. sci.):
Main properties of the classical Cepheids, adviser B.V.Kukarkin
Sternberg Institute, Moscow University, 1967
Dr. Sci. (Doctor phys.-mathemat. sci.): Cepheids and star groupings
Sternberg Institute, Moscow University, 1983
2000 -present Main sciential fellow, Sternberg Astronomicl
Institute (SAI) of Moscow State University
1989 - 2000 Head of the Department for Galactic and
Variable Stars Researches, SAI
1986 - 1989: Leading Scientific Fellow, SAI
1973 - 1986: Senior Scientific Fellow, SAI
1960 - 1973: laborant, aspirant, junior scientific fellow,
Astronomical Counsil of the USSR Academy of Sciences
Member of the International Astronomical Union, its Commissions 27,
33 (member of OK) and 37 (Variable stars, Structure of the Galaxy,
the member of editorial boards of the magazines
Astrophysical and Astronomical Transactions and
Fundamentals of Cosmic Physics.
The member of the Counsil for Astronomy
of the Russian Academy of Sciences.
Some more important scientific publications (of the total ~200):
1) Classical Cepheids. In book: Pulsating stars, J.Wiley & Sons, 1975
2) Period - age relation for Cepheids, Sov. Astr. 22, 161, 1978
3) Star complexes. Sov. Astr. Lett. 4, 68, 1978.
4) Nature of star complexes, Sov. Astr. Lett. 5, 12, 1979.
8) Open clusters, associations and complexes. Sov. Sci. Rev./Sec. E,
Astroph. Space Phys. Rev. vol. 7, part 2, 105 - 182,
Harwood: London, 1989
9) Ochagi zvezdoobrazovania v galacticakh: zvezdnie compleksy i spiralnye
rukava (Origins of star formation in galaxies: star complexes and
spiral arms), Moscow, Science Publ., 1989
10) Star complexes and evolutionary processes in spiral galaxies,
Vistas in Astronomy, 38, 165-205, 1994 (with A.D.Chernin)
11) Stellar complexes and associations: fundamental and elementary scales
of star formation. AJ, 110, 2757, 1995
12) An extension of hierarchical star formation to galactic scale
Astroph. J., 466, 802-807, 1996
13) An objective determination of blue star groupings in
the Andromeda galaxy
Battinelli, P. and Magnier E. A.
Astron. Astrophys., 314, 51-58 (1996)
14) On the nature of the vertical structure of the galactic disk
Rev. Mex. Astr. Conf. Ser. 4, 1, 1996.
15) A Universal Formation Mechanism for Open and
Globular Clusters in Turbulent Gas
Astrophys. J..v.480, pp. 235 - 245, 1997
16) Giant shells and stellar arcs as relics
of Gamma-rays burst explosions
ApJ Lett., 501, L163, 1998
B.Elmegreen and P.Hodge
17) Hierarchical star formation from the time-space distribution
of star clusters in the Large Magellanic Cloud
Mon. Not. RAS, 299, 588, 1998
18) A comparative study of spatial distribution of Cepheids and clusters
in the Large Magellanic Cloud
Astron. Astroph., 346, 778, 1999
19) Stellar arcs and gamma-ray bursts
Astron. Lett., 25, 74 - 79, 1999
20) Gamma-rays bursts versus OB-associations: do they trigger
Astron. Astrophys., 350, 457-468, 1999.
with S.Ehlerova and J.Palous
21) B.G.Elmegreen, Yu.N.Efremov, R.E.Pudritz and H.Zinnecker
In: Protostars and Planets IV eds. V.Mannigs, A.P.Boss and S.S.Russel
Univ. Arizona Press, Tucson, 2000, pp. 179-215>
Observations and theory of star cluster formation
22) A.K.Dambis and Yu.N.Efremov
Journal for History of Astronomy, 31, 115-134, 2000
Dating Ptolemy's star catalogue through proper motions:
the Hypparchan epoch
23) B.G.Elmegreen, Yu.N.Efremov, S.Larsen
Astrophys. J., 535, 748 - , 2000
A young globular cluster in the galaxy NGC 6946
24) Yu.N.Efremov. On the nature of peculiar stellr complexes.
Rus. Astron. J., 79, #10 (2002)
25) Efremov Yu.N., Pustilnik S.A., Kniazev A.Y. et al.
6-m telescope spectroscopic observations of the bubble
complex in NGC 6946.
Astron. Astroph., 389, 855, 2002.
26) Larsen S.S., Efremov, Yu.N., Elmegreen B.G. et al.
Hubble space telescope imaging of a peculiar
stellar complex in NGC 6946.
Astroph. J., 567, 896, 2002.
27) Yu.N.Efremov, A.D.Chernin.
Large scale star formation in galaxies.
Physics Uspechi, 173, 3-25, 2003.
28) Yu.N.Efremov. Cepheids in the LMC clusters and
the period - age realation
Rus. Astron. J., 80, 3-15, 2003.
29) Yu.N.Efremov, E.Alfaro, P.Hodge, Larsen S., Munoz-Tunon C.
A peculiar stellar complex in NGC 6946 or the blue compact
galaxy in front of this galaxy?
Astron. Astroph. Trans., 23, 95-101, 2004.
30) Yu.N.Efremov. Superassociations and stellar complexes in galaxies.
Astrophysics, 47, 273-286, 2004.
The author of many popular writings, including the book:
Into Depth of the Universe, the last 4th edition: Moscow, URSS Editorial,
2003. The book was translated into German (three editions),
Hungarien and Bulgarien. In 2005 Efremov's book "Islands of Stars"
was published by "Vek-2" Publishers (in Russian). His name was recently
given to the minor planet (12975) Efremov = 1973 SY5 (Minor Planet
Circular # 54562, 2005 July 21).
Graduated from the Moscow University in 1960, during 1960 - 1973
participated in the compilation of the variable stars catalogues under
the leadership of B.V.Kukarkin; the co-author of
the Third Edition of the General Catalog of Variable Stars and of
the Second Catalog of Stars, suspected in Variability.
Yu.N.Efremov and P.N.Kholopov were first (1965, 1975) to investigate
the only double Cepheid in an open cluster (CE Cas) and the only
double-mode Cepheid in a cluster (V369 Sct). Another early finding by
Yu.N.Efremov was the discovery of the light variability of the optical
counterpart of the quasar 3C 273 (simultaneously with H.Smith, 1963)
and the first identification of HZ Her as the optical counterpart to
the X-rays source Her X-1 (1973).
The observational evidences of the existence of the period - age relation
for Cepheids were presented by Yu.Efremov first in 1964 and with
much more data in 1978 and in 2003. He was first to use the Cepheids
in studying the history of star formation in galaxies: the larger
period, the younger is the Cepheid. This relation was then used in studies
of distribution of young stars in the Andromeda galaxy, resulted in
discovery the age gradient in the spiral arm S4 of that galaxy,
predicted by the density wave theory of the spiral structure.
The Cepheids were later used to establish the existence of the vast
groupings of co-formed young stars and clusters named by Yu.Efremov
the star complexes. These complexes were investigated in our
Galaxy, in the Andromeda, Triangulum and other galaxies; the brightest
complexes were proved to be the star clouds delineating the spiral
arms of the galaxies. The hierarchical organisation of embedded star
groupings, of which the complexes are the largest and oldest ones,
was investigated in papers with P.Batinelli. The location of star
complexes in the Galaxy was studied in papers with E.Alfaro,
L.Berdnikov and T.Sitnik.
In a number of joint papers with B.Elmegreen the large-scale hierarchical
and triggered star formation in the turbulent gas was explored. The universal
mechanism of formation of open and globular clusters was also suggested.
In the joint paper with A.D.Dambis the millenium issue of
the history of astronomy was resolved: the proper motions of stars have
proved that coordinates of stars in the Almagest catalogue were
observed by Hipparcos, not Ptolemy, contrary to what the latter claimed.
A number of peculiar stellar complexes was found in recent years.
Yu.Efremov has initiated the investigation, at the world largest
telescopes, the most interesting complex in NGC 6946, which hosts
the young massive cluster, the only known supercluster at the outskirts of
a normal spiral galaxy. The star/cluster complexes in M51 are now under
investigation in joint works with N.Bastian, M.Gieles, H.J.Lamers et al.
The citation account in ADS is ~1230 (2005 November). Yu.N.Efremov is
amongst ~700 Russian scientists having more than 1000 citations.