Re: TO Amara Re: Chandra and black hole abundance

From: Amara Graps (
Date: Mon Jan 17 2000 - 16:01:16 MST

From: Robert Bradbury ( Sat, 15 Jan 2000:

>Its worth noting the distinction between the "quasar" class
>supermassive black holes (~1/galaxy)

Or sometimes 2, but they coalesce pretty quickly or else are ejected
from the star cluster. I heard today of a neat theory for OJ 287,
which is a BL Lacertae object (an active galactic nuclei also called
"BL Lacs" or "blazars"). The theory describes the BL Lac with a
black hole in orbit around it and professes to explain OJ 287's
extremely energetic and short-lived outbursts. The object OJ 287 is
one of the most variable BL Lacs, and is famous among BL Lac
researchers because it has large amplitude, short time-scale
variations in wavelengths from radio to optical, and it displays
activity on time scales as small as 10 minutes.

Yes, these supermassive black holes are a different beast than the
black holes that are the end state of massive stars, and a different
beast from the baby black holes from the early formation of the
Universe. I even saw something in the ADS abstracts describing
"nuclear" black holes, which are smaller than supermassive black
holes, but larger than the stellar-sized black holes.

[I'm no black hole expert.. I'm working at the other end of the
Universe scale with ~nano-sized particles...]

I found these quotes:

"Supermassive black holes seem to be generic components of galactic
nuclei. From their formation in the early universe, black holes
often find themselves as a consequence of galaxy mergers." [from
"Black Holes and Galaxy Evolution", Merritt, David, in _Dynamics of
Galaxies_, 15th IAP meeting in Paris, France, July 1999, ASP
Conference Series, Vol 197, p. 221]

and R. Blandford says: "Beyond all reasonable doubt, black holes are
commonly found in the nuclei of most normal galaxies" [from "Origin
and Evolution of Massive Black Holes in Galactic Nuclei", Blandford,
R.D., _Galaxy Dynamics_ conference held at Rutgers U, Aug 1998, ASP
Conference Series Vol 182]

>I think we need a reality check here. If we have between 200 and 400
>*billion* stars in the galaxy that means we have 1 black hole per
>few thousand stars??? This might be right but someone like Amara
>should comment on whether the Initial Stellar Mass Function
>distribution would produce supernovas resulting in black holes for
>~1 in 1000 stars.

How about this. We know that black holes are the products of stars
with initial masses exceeding ~20-25 M_solar. A Scalo (1986) mass
distribution with a lower mass limit of 0.1 M_solar and an upper
limit of 100 M_solar has a 0.071% of its stars more massive than 20
M_solar and 0.045% more massive than 25 M_solar, respectively. A
star cluster containing N stars thus produces ~6 * 10^{-4} N black
[From Zwart, S. and McMillan, S. (2000) "Black hole mergers in the
universe", ApJL 528: L17-L20, January 1 2000.]

An Aside: A Scalo mass distribution is something standard in
astronomy for defining initial mass functions for stars in clusters
and galaxies. Here is the reference:

Scalo, J.M. (1986) "The stellar initial mass function"
Fundamentals of Cosmic Physics 11, May 1986, p. 1-278.

The existing observational database on the stellar mass distribution
is reviewed as the basis for defining a new estimate of the field
star mass function and its sources of error. A valid initial mass
function (IMF) is desirable in order to gain the capability of
tracking the chemical evolution and abundances of stars and
galaxies. Several parameterized versions of the IMF are discussed
and illustrated with examples. The field star IMF is introduced for
estimating the stellar mass function by determining the frequency
distribution of luminosities for field stars in the solar
neighborhood. The distribution is converted into a distribution of
masses by means of a mass-luminosity relation and corrected for
stars that have died over the history of the galactic disk. The
results are applied to the solar neighborhood, compared with
calculations using other models, and then extended to calculating
IMFs for star clusters, nearby galaxies, and chemical distributions
within galaxies.

>I think we need some "scientific source" URLs (rather than quotes
>from papers extracted from press releases).

The NASA-ADS is probably the best place. I tried today with
keywords: "supermassive black holes galaxies" and I got hundreds of
papers. This paper might be good place to start: "The Search for
Supermassive Black Holes in Galaxy Nuclei" Annu. Rev. Astron.
Astrophys. 1995. 33: 581-624

The NASA ADS query results are a bit overwhelming.... (too many
to go through in the little time I had)

Here are some related URLs:

Chandra Xray Observatory

And some other fun URLs:

Ned Wright Cosmology News

Martin White HTML papers

Richard McCray's Cosmology Tutorial

Dark Matter Flowchart

Also the following announcement of a conference that already
occurred will give you the key people working in the field, with
their areas of expertise. Once you have the names, you can narrow
down the NASA ADS search somewhat.


                           ESO WORKSHOP ON
            their Diagnostics, Demography, and Formation

                   In honour of Prof. R. Giacconi

                         September 6-8, 1999
           ESO Headquarters, Garching bei Muenchen, Germany

The aim of this workshop is to bring together astrophysicists working
on the rather separate fields of stellar-mass and supermassive black
holes, with emphasis on the formation, population, physics, and
environments of black holes. An overview will be given of the
observational evidence for the existence of black holes in binaries
and galactic nuclei. Related topics like the late stages of (binary)
evolution and galaxy formation will be addressed.


Special Talk:

  R. Giacconi Black Holes: A Historical and Future Perspective.

Invited Review:

  M.C. Begelman General Overview: Black Holes in the Universe.
  P.A. Charles Black Holes in X-ray Binaries.
  R. Genzel The Dark Mass in the Center of the Milky Way.
  P.T. de Zeeuw Dynamical Evidence for the Presence of
                     Supermassive Black Holes in Galaxy Centers.
  Y. Tanaka X-ray Spectra Neutron Stars vs. Black Holes.
  R. Sunyaev Scaling Down from QSOs to Stellar Mass Black Holes.
  E.S. Phinney (*) The AGN Phenomenon in Relation to QSOs.
  R.D. Blandford Models for Jet Formation.
  R. Narayan Advection-dominated Accretion Flows.
  D.O. Richstone Supermassive Black Holes and Constraints on the
                     Evolution of Galaxies.
  M.J. Rees Scenarios for the Formation of Black Holes.
  F. Verbunt Binary Evolution and Black Hole Formation.
  J.A. Van Paradijs Gamma-ray Bursts in Relation to Black Hole Formation.
  S.D.M. White Galaxy Formation and Supermassive Black Holes.

Invited Talks:

  M.H. Van Kerkwijk Observed Neutron Star Masses.
  G. Srinivasan The Maximum Neutron Star Mass.
  A.M. Ghez Observing the Fastest Moving Stars in our Galaxy:
                     Evidence of a Supermassive Black Hole at the Center
                     of the Milky Way.
  K. Gebhardt Recent results on the Orbital Structure around
                     Supermassive Black Holes.
  R. Bacon A supermassive Black Hole and Asymmetries in the
                     M31 Double Nucleus.
  M. Van der Klis(*) Can one Discriminate Neutron Stars from Black Holes
                     on the Basis of their X-ray Variability?
  T. Belloni The X-ray Phenomenology of 1915+105.
  J.P. Lasota Why Tend BH X-ray Binaries to be Transients?
  R.P. Fender Observations of Jets in Stellar Black Hole Systems.
  I.F. Mirabel The Superluminal Jets of 1915+105.
  A.C. Fabian Black Hole Accretion Disks.
  C.D. Bailyn (*) Do Globular Clusters Contain Black Holes?
  R.P. Van der Marel Contraints on the Presence of a Central Black Hole
                     in M15, the Densest Galactic Globular Cluster.
  S.F. Portegies Zwart Numerical Simulations of Globular Cluster -
                     Theoretical Constaints on the Black Hole Formation.
  L.C. Ho AGN Demography: Bridging the Gap between "Normal"
                     and "Active" Galaxies.
  N. Langer The Advanced Evolution of Massive Stars.
  S.E. Woosley Physics of Core Collapse and the Formation of
                     Neutron Stars and Black Holes.
  V. Kalogera Formation of BH X-ray Binaries with Low-mass Donor Stars.
  K. Nomoto (*) Supernovae/Hypernovae: Diagnostics of Black Hole
  F.A. Rasio Numerical Simulations of Mergers of Double Neutron
                     Stars and Black Holes.
  M.G. Haehnelt High-redshift Galaxies, their Active Nuclei and
                     Central Black Holes.
  A. Renzini NGC 4552.

Workshop Summary:

Hope this helped,


Amara Graps | Max-Planck-Institut fuer Kernphysik
Interplanetary Dust Group | Saupfercheckweg 1
+49-6221-516-543 | 69117 Heidelberg, GERMANY *
        "Never fight an inanimate object." - P. J. O'Rourke

This archive was generated by hypermail 2b29 : Thu Jul 27 2000 - 14:02:21 MDT