Trying to Understand the Milky Way's Black Hole

Gabriele Ponti
Gabriele Ponti

Dr. Gabriele Ponti is the Marie Sklodowska-Curie EU Research Fellow at the Max Planck Institute for Extraterrestrial Physics in Germany. Prior to that, he was a post-doctoral fellow at the University of Southampton in the UK, after spending a year at Cambridge University’s Institute of Astronomy. Dr. Ponti earned his Ph.D. from Bologna University in Italy before moving on to the Laboratories Astro-Particule et Cosmologie in Paris. His doctoral thesis topic was studying relativistic effects in bright active galactic nuclei and he has been interested in this area since then.

As a boy, I read about the existence of black holes for the first time. I still remember the fascination of trying to grasp the physical concepts behind one of the weirdest manifestations of nature.

Black holes produce an enormous gravitational pull, as a consequence of being extremely compact: a significant amount of mass concentrated in a very small volume.

Milky Way's Black Hole Shows Signs of Increased Chatter

SgrA*
Three orbiting X-ray telescopes have been monitoring the supermassive black hole at the center of the Milky Way galaxy for the last decade and a half to observe its behavior. This long monitoring campaign has revealed some new changes in the patterns of this 4-million-solar-mass black hole known as Sagittarius A* (Sgr A*).

Interning with Chandra

Alicia Goldstein
Alicia Goldstein

We welcome Alicia Goldstein, who was an intern at the Chandra X-ray Center this past summer, as our guest blogger. Ms. Goldstein, originally from Ellicott City, MD, is currently a senior at the University of Maryland, Baltimore County where she majors in mechanical engineering. Prior to this summer, Ms. Goldstein was an intern at NASA’s Goddard Space Flight Center and lists working for NASA as her ideal career goal.

This summer, I worked on two separate projects. The first involved the development of a Python code that would display the defined and predicted positions and velocities of Chandra, and the second involved the analysis of the periods of the variable stars in the Chandra Variable Guide Star Catalog,, or VGuide, database. The coding project involved interpreting and manipulating previous code, as well as creating entirely new sections. Given an input of two data files, the code was able to output a file with plots of the predicted and defined velocities and positions of the spacecraft.

Chandra Data Suggest Giant Collision Triggered "Radio Phoenix"

Abell 1033
Astronomers have found evidence for a faded electron cloud "coming back to life," much like the mythical phoenix, after two galaxy clusters collided. This "radio phoenix," so-called because the high-energy electrons radiate primarily at radio frequencies, is found in Abell 1033. The system is located about 1.6 billion light years from Earth.

The Hunt for the Smallest Supermassive Black Holes

Vivienne Baldassare
Vivienne Baldassare

We are very pleased to welcome Vivienne Baldassare as a guest blogger today. Vivienne is the first author of a paper that is the subject of our latest press release, about an exceptionally small supermassive black hole. She is a PhD candidate and National Science Foundation Graduate Research Fellow in the University of Michigan Department of Astronomy. Vivienne obtained her undergraduate degree in physics from Hunter College, where she was also a member of the Macaulay Honors College.

It is well established that most, if not all, massive galaxies host supermassive black holes at their centers − our own Milky Way houses a several million solar mass black hole in its core. Little is known, however, about the population of black holes in the centers of dwarf galaxies. I study the centers of small galaxies to see how many host supermassive black holes and if those black holes interact with their galaxies in the same way as bigger supermassive black holes.

Though dwarf galaxies are more common than large galaxies, it is more difficult to determine whether they host black holes. When galaxies are large and nearby, we can find central black holes by studying the motions of stars in the region dominated by the gravity of the black hole. Since smaller black holes influence smaller regions, this method would only work for dwarf galaxies in our cosmological back yard. Instead, we must search for active black holes in dwarf galaxies, i.e. black holes that are voraciously consuming material, releasing large amounts of light from the galaxy’s center.

Oxymoronic Black Hole Provides Clues to Growth

RGG 118
Astronomers using NASA's Chandra X-ray Observatory and the 6.5-meter Clay Telescope in Chile have identified the smallest supermassive black hole ever detected in the center of a galaxy, as described in our latest press release. This oxymoronic object could provide clues to how much larger black holes formed along with their host galaxies 13 billion years or more in the past.

Pages

Disclaimer: This service is provided as a free forum for registered users. Users' comments do not reflect the views of the Chandra X-ray Center and the Harvard-Smithsonian Center for Astrophysics.
Please note this is a moderated blog. No pornography, spam, profanity or discriminatory remarks are allowed. No personal attacks are allowed. Users should stay on topic to keep it relevant for the readers.
Read the privacy statement