Byurakan Astrophysical Observatory

06/12/2020

21/09/2020

Our most recent Picture of the Week shows the winds around a star called R Aquilae. A research team, using ALMA Observatory to look at stellar winds blowing out from around a dozen red giant stars, found that the stellar winds were not spherical as expected, but had different shapes, including some resembling the delicate petals of a rose.

Image credit: ALMA (ESO/NAOJ/NRAO), Decin et al. http://orlo.uk/wAOAb

21/09/2020

• SNR 0454-67.2. • Tangled - Cosmic Edition
20.9.2020

• This dark, tangled web is an object named SNR 0454-67.2. It formed in a very violent fashion — it is a supernova remnant, created after a massive star ended its life in a cataclysmic explosion and threw its constituent material out into surrounding space. This created the messy formation we see in this NASA/ESA Hubble Space Telescope image, with threads of red snaking amidst dark, turbulent clouds.

SNR 0454-67.2 is situated in the Large Magellanic Cloud, a dwarf spiral galaxy that lies close to the Milky Way. The remnant is likely the result of a Type Ia supernova explosion; this category of supernovae is formed from the death of a white dwarf star, which grows and grows by siphoning material from a stellar companion until it reaches a critical mass and then explodes.

As they always form via a specific mechanism — when the white dwarf hits a particular mass — these explosions always have a well-known luminosity, and are thus used as markers (standard candles) for scientists to obtain and measure distances throughout the Universe.

• About the Object:
Name: SNR 0454-67.2
Type: Local Universe : Nebula : Type : Supernova Remnant
Distance: 163000 light years
Constellation: Dorado
Position (RA): 4 54 31.32
Position (Dec): -67° 12' 55.72"
Field of view: 2.60 x 2.75 arcminutes
Orientation: North is 185.5° left of vertical

• Zoomable Image: https://www.spacetelescope.org/images/potw1848a/zoomable/
• Source: http://www.esa.int/ESA_Multimedia/Search/(offset)/150/(sortBy)/published?result_type=images&SearchText=galaxies

• Credit: ESA/Hubble, NASA; CC BY 4.0

15/09/2020

Solar Cycle 25 is underway! Today a consortium of solar science experts, including Dr. Gordon Petrie from National Science Foundation (NSF)’s NSO, reached a consensus on the next solar cycle. Astronomers predict it will be very similar to the last, breaking a weakening trend seen over the past four cycles!
http://ow.ly/xmkB50BrvmA

Happening now (Today, 1pm EDT) NASA - National Aeronautics and Space Administration and National Oceanic and Atmospheric Administration (NOAA) are holding a media teleconference to discuss the predictions for the upcoming solar cycle. Find it at: www.nasa.gov/live

15/09/2020

14/09/2020

The Heart of the Lagoon Nebula --- Spectacular Hubble image revealing the heart of the Lagoon Nebula. Seen as a massive cloud of glowing dust and gas, bombarded by the energetic radiation of new stars, this placid name hides the dramatic interplay between gas and dust sculpted by intense radiation from hot young stars deep in the heart of the nebula. Credit: NASA/ESA - HST

14/09/2020

• NGC 2835 • Eye of the Serpent
- PHANGS-HST galaxy survey
14.9.2020

• The twisting patterns created by the multiple spiral arms of NGC 2835 create the illusion of an eye. This is a fitting description, as this magnificent galaxy resides near the head of the southern constellation of Hydra, the water snake. This stunning barred spiral galaxy, with a width of just over half that of the Milky Way, is brilliantly featured in this image taken by the NASA/ESA Hubble Space Telescope. Although it cannot be seen in this image, a supermassive black hole with a mass millions of times that of our Sun is known to nestle in the very centre of NGC 2835 .

This galaxy was imaged as part of PHANGS-HST, a large galaxy survey with Hubble that aims to study the connections between cold gas and young stars in a variety of galaxies in the local Universe. Within NGC 2835, this cold, dense gas produces large numbers of young stars within large star formation regions. The bright blue areas, commonly observed in the outer spiral arms of many galaxies, show where near-ultraviolet light is being emitted more strongly , indicating recent or ongoing star formation.

Expected to image over 100 000 gas clouds and star-forming regions outside our Milky Way, this survey hopes to uncover and clarify many of the links between cold gas clouds, star formation and the overall shape and morphology of galaxies. This initiative is a collaboration with the international Atacama Large Millimeter/submillimeter Array (ALMA) and the European Southern Observatory's Very Large Telescope's MUSE instrument, through the greater PHANGS program (PI: E. Schinnerer).

• About the Object:
Name: NGC 2835
Type: Milky Way : Galaxy : Type : Spiral
Constellation: Hydra
Position (RA): 9 17 53.09
Position (Dec): -22° 21' 16.14"
Field of view: 2.68 x 2.60 arcminutes
Orientation: North is 4.5° right of vertical

• Source: ESA/Hubble
• Credit: ESA/Hubble & NASA, J. Lee, and the PHANGS-HST Team
Acknowledgement: Judy Schmidt (Geckzilla)

13/09/2020

HUMANITY'S BUBBLE

This image superimposes the extend of radio broadcasts from Earth over an artist's conception of the Milky Way. Our radio transmissions have been slowly expanding into the deep reaches of space for about a century. As seen in the lower left corner, the extent of our communications is depicted as a small bubble just over 100 light-years across. Note that this is not represented by the square section, but by the small bluish dot indicated by the arrow.

The broadcasts travelling through space are weakened as they approach the Shannon limit, at which the energy of the signals is so low that they are no longer transmitting data and are almost indistinguishable from the background radiation.

-RLO

Source: https://www.planetary.org/space-images/extent-of-human-radio-broadcasts
Image Credit: Diagram by Adam Grossman, Milky Way illustration by Nick Risinger

12/09/2020

Spiral galaxy NGC 3190 from ESO's Very Large Telescope...Good Morning, Earthlings! I wish everybody a fantastic day! Credit: NASA .

11/09/2020

• Galactic Census Reveals Origin of Most "Extreme" Galaxies
10.9.2020

IMAGE: A wide field view of the central region of the Virgo Cluster, measuring 4.4 million light years on each side, from the Sloan Digital Sky Survey. Some of Virgo's brightest member galaxies are labeled, including Messier 87, or M87, which is located close to the cluster center. Insets show deep images of two structurally extreme galaxies, taken with the MegaCam instrument on CFHT as part of the Next Generation Virgo Cluster Survey. An ultra-compact dwarf is within the crosshairs in the lower inset, while an ultra-diffuse galaxy is featured in the upper inset. These galaxies are nearly a thousand times fainter than the bright galaxies visible on this image. Although the compact and diffuse galaxies contain roughly the same number of stars, and their total brightness is similar, they differ in area by a factor of more than 20,000. The scale bars in each inset represent a distance of 10,000 light years. [Image credits: Sloan Digital Sky Survey, Canada-France-Hawaii Telescope and the NGVS team.]

• Astronomers have found that the key to understanding galaxies with "extreme" sizes, either small or large, may lie in their surroundings. In two related studies, an international team found that galaxies that are either "ultra-compact" or "ultra-diffuse" relative to normal galaxies of comparable brightness appear to reside in dense environments, i.e., regions that contain large numbers of galaxies. This has led the team to speculate that these "extreme" objects could have started out resembling normal galaxies, but then evolved to have unusual sizes through interactions with other galaxies.

The team identified both ultra-compact and ultra-diffuse galaxies as part of an unprecedented census of galaxies residing in the nearby Virgo cluster. At a distance of 50 million light years, Virgo is the galaxy cluster nearest to the Milky Way, and contains several thousand member galaxies, the majority of which are revealed, for the first time, in the NGVS data.

Astronomers discovered ultra-compact dwarf galaxies (UCDs) a quarter century ago, and they are the densest known galaxies in the Universe. Competing theories describe UCDs as either large star clusters, or as the remnants of larger galaxies that have been stripped of their stellar envelopes.

• Continue Reading: https://www.cfht.hawaii.edu/en/news/ExtremeGalaxies/

• Research PAPER: "The Next Generation Virgo Cluster Survey. ###IV. Ultra-Compact Dwarf (UCD) Galaxies in the Virgo Cluster" Chengze Liu et al, 2020: https://arxiv.org/abs/2007.15275