M101: Spitzer finds “No-organic” Zone

July 23, 2008

[M101 in IR, SST]

Spitzer Space Telescope was used to obtain this gorgeous false-color IR image of M101. Astronomers have found from these data that some special organic molecules, so-called polycyclic aromatic hydrocarbons, decrease in concentration toward the outer portion of the Pinwheel galaxy, and then quickly drop off and are no longer detected at its very outer rim.

Spitzer Press Release:

M4: Chandra locates X-ray sources and binaries

July 17, 2008

[M4 in X-rays, CXO]

Globular clusters M4 and NGC 6397 have got their central parts imaged by Chandra X-ray Observatory, among a total of 13 Milky Way Globular Clusters. Astronomers found that contrary to expectation, denser M4, with its higher rate of stellar encounters, has less binaries and hot X-ray sources than less dense NGC 6397.

Credit: NASA/CXC/Northwestern Univ/John Fregeau

Chandra image:

Chandra Press Release (April 28, 2008):

SEDS M4 page:

M60: New Chandra Image gives mass of central object

July 17, 2008

[M60, x-ray/optical composite, CXO/HST]

Data obtained with the Chandra X-ray Observatory (CXO) have been used to create this image of the Virgo Cluster giant elliptical galaxy M60 (NGC 4649), and to estimate the mass of the central object of this galaxy. This object, thought by many astronomers to be a supermassive black hole, was found to have a mass 3.4 billion times that of the Sun, or about 1,000 times more than the object in the Milky Way’s center.

Credit: X-ray (NASA/CXC/Univ. of California Irvine/P.Humphrey et al.); Optical (NASA/STScI)

Chandra Image:

Chandra Press Release:

SEDS M60 page:

Recent Images and News of Messier Objects

July 15, 2008

M4 (and NGC 6397) from Chandra; April 28, 2008:

M31 and M101 by Galex, February 21, 2008:

M81 from Chandra; June 18, 2008:

M81 group (in particular, Arp’s Loop), from Hubble; January 8, 2008:

M81 group with radio clouds, from NRAO; January 10, 2008:

M82 in X-rays by XMM Newton:

M83 by Galex; April 16, 2008:

M106 by Galex; April 28, 2008:

Various THINGS galaxies, including M51, M63, M74, M81 and several M81 group dwarfs, by NRAO; January 10, 2008:

M51: New Chandra/Hubble image of the Whirlpool Galaxy

January 25, 2008

Nasa’s big space observatories, Chandra (CXO), GALEX, Hubble (HST), and Spitzer (SST) have been used to obtain a new, gorgeous composite image in multiple parts of the spectrum: The X-ray, UV, optical, and infrared part, respectively.

Credit: X-ray: NASA/CXC/Wesleyan Univ./R.Kilgard et al; UV: NASA/JPL-Caltech; Optical: NASA/ESA/S. Beckwith & Hubble Heritage Team (STScI/AURA); IR: NASA/JPL-Caltech/ Univ. of AZ/R. Kennicutt

Chandra Press Release:

Spitzer Press Release:

SEDS M51 page:

M49, M84, M89: Chandra Views Galactic Nuclei in X-rays

January 25, 2008

The nuclei of M49, M84, and M89 as seen by Chandra in X-ray light.

Nasa’s Chandra X-ray Observatory has been used to observe the Massive Objects in the Galactic Nuclei of the galaxies M49, M84, M89, and NGC 5846. These investigations provide one of the best pieces of evidence yet that many supermassive central objects in galaxies are spinning extremely rapidly. These images show pairs of huge bubbles, or cavities, in the hot gaseous atmospheres of the galaxies, created in each case by jets produced by a central supermassive object, thought to be black holes by many astronomers. Studying these cavities allows the power output of the jets to be calculated.

The four images released to the press are just a fraction of the total of nine galaxies surveyed in this investigation.

Chandra Press Release:

SEDS page of M49:
SEDS page of M84:
SEDS page of M89:

M33: Stellar BH candidate M33 X-7

December 12, 2007

Credit: Illustration: NASA/CXC/M.Weiss; X-ray: NASA/CXC/CfA/P.Plucinsky et al.; Optical: NASA/STScI/SDSU/J.Orosz et al.

Chandra X-ray Observatory and Hubble Space Telescope images have been used to investigate this bright X-ray source in M33. The object is thought to be a stellar-mass black hole candidate, with a dark object of 16 solar masses in orbit around a star of about 70 solar masses.

Chandra Image:
Chandra Press Release:

SEDS M33 page:

M42: Chandra image of the Orion Nebula

October 12, 2007

Credit: X-ray: NASA/CXC/Penn State/E.Feigelson & K.Getman et. al.; Optical: NASA/ESA/STScI/M. Robberto et.al.

Nasa’s Chandra X-ray Observatory has been used to obtain a deep look into the Orion Nebula M42 in X-rays. This image was combined with Hubble Space Telescope optical images for the composite image shown above. Shown is the cluster of young stars currently forming in the Orion Nebula (Orion Nebula Cluster or Trapezium Cluster).

The bright point-like sources (blue and orange) in this image are the burgeoning stars captured in X-ray light by a long series of Chandra observations. These nearly continuous observations, lasting almost 13 days, allowed astronomers to monitor the activity of Sun-like stars between 1 and 10 million years old. The fledgling stars were seen to flare in their X-ray intensity much more than our Sun does today. This suggests our Sun had many violent and energetic outbursts when it was much younger. The wispy filaments (pink and purple) are clouds of gas and dust as seen by Hubble in optical light. This gas and dust will one day condense into disks of material from which future generations of stars will be born.

Chandra Press Release:

SEDS M42 page:

Messier Catalog: Scans online

September 24, 2007

Scans of the historical Messier Catalog, published 1781 in the Connoissance des Temps for 1784, are available online at:


M1: Crab Pulsar Discovery

August 22, 2007

Steinn Sigurdson reports that the Crab Pulsar, and consequently other pulsars, have been discovered months earlier than previously known, in summer 1967, by US Air Force officer Charles Schisler on duty.

Charles was on radar duty at Clear USAFB Alaska in summer 1967, when he noticed and logged a fluctuating radio source which was not moving, i.e. at fixed RA and Dec. The next day it was there again, and when he determined its position, he identified it with the Crab Nebula. Subsequently, he found a number of further pulsars.

USAF decided that this was not their business, and didn’t publish his findings. Therefore, Joycelyn Bell independently found her first pulsar a couple of months later.

Full story:

SEDS M1 page: