Galaxies

Soon after the Big Bang, the Universe became a space filled with "stuff:" neutral gas, dark matter, and radiation. After several hundred million years, primitive structures began to form from the first chemical elements, creating the first massive stars and eventually the first galaxies.

X-ray Sources in Galaxies

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M31

In all galaxies near enough to be studied in detail with Chandra (and this includes galaxies as far as at least 20Mpc), we observe populations of X-ray sources, with characteristics (time variability and spectra/X-ray colors) consistent with those of the X-ray binary stars found in the Milky Way: these sources are powered by the outer layers of a normal star falling into a neutron star or a black hole; observing different types of galaxies (elliptical, spiral, starburst and interacting), we can begin to understand how these X-ray sources form and evolve and how their history is linked to th

Interacting Galaxies & Mergers

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Antennae galaxy

Galaxy interaction and merging is seen throughout the universe, and it is believed to be an important mechanism in galaxy formation and evolution; large elliptical galaxies may be the remnants of past mergers. The effect of interaction and merging can be seen in distorted and asymmetric galaxy morphologies and in the presence of tidal tails.

Starburst Galaxies

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M82

Starbust galaxies are either young or rejuvenated galaxies, with a star formation activity significantly larger than in our own Milky Way. These galaxies typically contain very luminous X-ray sources, including the Ultra-luminous X-ray sources (ULXs) that may harbor massive black holes (see X-ray sources in galaxies).

Normal Galaxies

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M83

Normal galaxies were first observed in the X-rays with the Einstein Observatory, the first X-ray telescope to observe the deep universe, launched by NASA in 1978 and developed under the leadership of the CfA HEA. This first look at the X-ray emission of galaxies revealed bright point-like sources and diffuse emission. With the Chandra X-ray Observatory we are now studying the X-ray emission of galaxies in exquisite details. We detect populations of luminous and variable point-like X-ray sources, diffuse emission from hot gas and in some cases emission from active nuclei.

Clusters of Galaxies

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Clusters of galaxies are the most massive gravitationally bound objects in the universe. OIR scientists study images and spectra of clusters to determine their masses, distribution, and the properties of the clusters and their member galaxies. The large velocities of cluster galaxies provided the first evidence of dark matter. Today, scientists continue to study clusters to understand how dark matter and galaxies are connected.

OIR Detector Lab

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The OIR Laboratory provides design, development, construction, deployment, and repair/maintenance services in the area of solid-state imaging detectors and their associated electronics for astronomical instrumentation. Some of the more detailed capabilities are:

Starburst Galaxies

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The most luminous galaxies in the universe are over a thousand times more powerful than our Milky Way...yet they are not especially bright at optical wavelengths! They were instead discovered in the infrared. It seems they are powered by bursts of massive star formation: clusters of massive stars, each star thousands or even tens of thousands of times more luminous than our Sun, and all of them buried in dusty natal clouds of material that block their visible light.

Merging and Interacting Galaxies

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Mid-infrared Surveys of Nearby Interacting Galaxies

Normal Galaxies

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The nearby universe contains "normal" galaxies of a variety of different, morphological types: elliptical, lenticular, spiral, dwarf, and irregular. Current research in the OIR Division investigates the luminosities, masses, stellar content, ages, star formation histories, and dust content of these galaxies. Many of these projects have been based on galaxies drawn from redshift surveys done at CfA over the last three decades.

Milky Way Center

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Observations of stellar orbits provide overwhelming evidence for a massive black hole lurking in the heart of the Milky Way. The Galactic Center is also densely packed with stars and star clusters containing the most massive stars known in the Galaxy. If the Earth were located in the Galactic Center, night would be as bright as day from the light of hundreds of stars blazing in the sky. A massive black hole in such a crowded environment will inevitably sling-shot a few unlucky stars straight out of the Milky Way.

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