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Groups & Clusters of Galaxies
X-ray Astronomy Field Guide
Groups & Clusters of Galaxies
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Groups & Clusters of Galaxies
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Groups & Clusters of Galaxies
Cosmology/Deep Fields/X-ray Background
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A Tour of Perseus
A Tour of Perseus (2014-06-25)
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Illustration of Sunyaev-Zeldovich Effect
(Illustration: NASA/CXC/M.Weiss)

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CL 0016+1609:
Chandra Independently Determines Hubble Constant


CL 0016+1609
Credit: NASA/CXC/MSFC/M.Bonamente et al.

These six galaxy clusters are a subset of the 38 that scientists observed with Chandra, with distances ranging from 1.4 to 9.3 billion light years from Earth, to help determine the Hubble constant. The Hubble constant, or the Hubble parameter, is a critically important number that sets the expansion rate of the Universe, and is derived by measuring the speeds that the clusters are moving away from us and dividing by the cluster distances.

A combination of X-ray and radio observations allowed astronomers to determine the Hubble constant using the so-called Sunyaev-Zeldovich effect. In this phenomenon, photons in the cosmic microwave background (CMB) interact with electrons in the hot gas that pervades the enormous galaxy clusters. The photons acquire energy from this interaction, which distorts the signal from the microwave background in the direction of the clusters. The magnitude of this distortion depends on the density and temperature of the hot electrons and the physical size of the cluster.

Astronomers used radio telescopes to measure distortions of the cosmic microwave background. Chandra measured the properties of the hot gas revealed in X-ray emission, which told astronomers the physical size of the galaxy clusters and thus allowed their distances to be determined.

The value for the Hubble constant derived from this method, which is independent of previous techniques, was found to be 76.9 in its traditional units of kilometers per second per megaparsec (a megaparsec is equal to 3.26 million light years.) Taking into account the small uncertainties, this result agrees with the values determined by other techniques, and fixes the age of the Universe between 12 and 14 billion years.

Fast Facts for CL 0016+1609:
Credit  NASA/CXC/MSFC/M.Bonamente et al.
Scale  Image is 4.4 arcmin across.
Category  Groups & Clusters of Galaxies, Cosmology/Deep Fields/X-ray Background
Coordinates (J2000)  RA 00h 18m 33.50s | Dec +16 26' 12.50
Constellation  Pisces
Observation Dates  18 Aug 2000
Observation Time  19 hours
Obs. IDs  520
Color Code  Intensity
Instrument  ACIS
References Determination of the Cosmic Distance Scale from Sunyaev-Zel'dovich Effect and Chandra X-ray Measurements of High Redshift Galaxy Clusters, M. Bonamente, Astrophysical Journal, 2006 August 10 (astro-ph/0512349)
Distance Estimate  About 5.3 billion (z=0.54) light years
Release Date  August 08, 2006
Fast Facts for Abell 665:
Credit  NASA/CXC/MSFC/M.Bonamente et al.
Scale  Image is 5.6 arcmin across.
Category  Groups & Clusters of Galaxies, Cosmology/Deep Fields/X-ray Background
Coordinates (J2000)  RA 08h 30m 58.10s | Dec +65º 50' 51.60"
Constellation  Ursa Major
Observation Dates  28 Dec 2002
Observation Time  8 hours
Obs. IDs  3586
Color Code  Intensity
Instrument  ACIS
References Determination of the Cosmic Distance Scale from Sunyaev-Zel'dovich Effect and Chandra X-ray Measurements of High Redshift Galaxy Clusters, M. Bonamente, Astrophysical Journal, 2006 August 10 (astro-ph/0512349)
Distance Estimate  About 2.2 billion (z=0.18) light years
Release Date  August 08, 2006
Fast Facts for MACS J1149.5+223:
Credit  NASA/CXC/MSFC/M.Bonamente et al.
Scale  Image is 4.2 arcmin across.
Category  Groups & Clusters of Galaxies, Cosmology/Deep Fields/X-ray Background
Coordinates (J2000)  RA 11h 49m 35.50s | Dec +22 24' 02.30
Constellation  Leo Minor
Observation Dates  01 Jun 2001, 07 Feb 2003
Observation Time  11 hours
Obs. IDs  1656, 3589
Color Code  Intensity
Instrument  ACIS
Also Known As MACS J0018.5+1626
References Determination of the Cosmic Distance Scale from Sunyaev-Zel'dovich Effect and Chandra X-ray Measurements of High Redshift Galaxy Clusters, M. Bonamente, Astrophysical Journal, 2006 August 10 (astro-ph/0512349)
Distance Estimate  About 5.3 billion (z=0.54) light years
Release Date  August 08, 2006
Fast Facts for CL J1226.9+3332:
Credit  NASA/CXC/MSFC/M.Bonamente et al.
Scale  Image is 4.4 arcmin across.
Category  Groups & Clusters of Galaxies, Cosmology/Deep Fields/X-ray Background
Coordinates (J2000)  RA 12h 26m 57.90s | Dec +33 32' 47.40
Constellation  Canes Venatici
Observation Dates  27 Jan 2003, 31 Jul 2000
Observation Time  12 hours
Obs. IDs  3180, 932
Color Code  Intensity
Instrument  ACIS
Also Known As 1WGA J1226.9+3332
References Determination of the Cosmic Distance Scale from Sunyaev-Zel'dovich Effect and Chandra X-ray Measurements of High Redshift Galaxy Clusters, M. Bonamente, Astrophysical Journal, 2006 August 10 (astro-ph/0512349)
Distance Estimate  About 7.3 billion (z=0.89) light years
Release Date  August 08, 2006
Fast Facts for Abell 1689:
Credit  NASA/CXC/MSFC/M.Bonamente et al.
Scale  Image is 8.1 arcmin across.
Category  Groups & Clusters of Galaxies, Cosmology/Deep Fields/X-ray Background
Coordinates (J2000)  RA 13h 11m 34.20s | Dec -01 21' 56.00
Constellation  Virgo
Observation Dates  07 Jan 2001, 15 Apr 2000
Observation Time  6 hours
Obs. IDs  1663, 540
Color Code  Intensity
Instrument  ACIS
References Determination of the Cosmic Distance Scale from Sunyaev-Zel'dovich Effect and Chandra X-ray Measurements of High Redshift Galaxy Clusters, M. Bonamente, Astrophysical Journal, 2006 August 10 (astro-ph/0512349)
Distance Estimate  About 2.2 billion (z=0.18) light years
Release Date  August 08, 2006
Fast Facts for Abell 1914:
Credit  NASA/CXC/MSFC/M.Bonamente et al.
Scale  Image is 7.6 arcmin across.
Category  Groups & Clusters of Galaxies, Cosmology/Deep Fields/X-ray Background
Coordinates (J2000)  RA 14h 26m 00.80s | Dec +37 49' 35.70
Constellation  Boötes
Observation Dates  03 Sep 2003, 21 Nov 1999
Observation Time  7 hours
Obs. IDs  3593, 542
Color Code  Intensity
Instrument  ACIS
References Determination of the Cosmic Distance Scale from Sunyaev-Zel'dovich Effect and Chandra X-ray Measurements of High Redshift Galaxy Clusters, M. Bonamente, Astrophysical Journal, 2006 August 10 (astro-ph/0512349)
Distance Estimate  About 2.1 billion (z=0.17) light years
Release Date  August 08, 2006