About Me

Hi there,

My name is Snehasish Bhattacharjee (Bilton). I have a master's in Astronomy from Osmania University and a bachelor's in Physics from the University of Calcutta. I created this blog (astrounit.blogspot.com) to communicate the latest progress and discoveries in space science. In this blog, you will get to know about various astrophysical stuff such as black holes, galaxies, dark matter, dark energy, inflation, big bang, etc. I have tried to explain and illustrate the findings in simple language without the use of technical astronomical terms so that you get the main idea behind each discovery. I hope you will learn many interesting things about astronomy from this blog. If you have any queries or suggestions, kindly send me an email at gigabiltonnn@gmail.com.

Cheers,

Bilton

Me in March 2020

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Astronomers discover a giant radio bridge connecting two galaxy clusters

A team of astronomers used deep radio observations from 53 MHz to 1.5 GHz with the LOFAR Low/High Band Antenna (LBA/HBA) arrays, the Jansky Very Large Array (JVLA) and the upgraded Giant Metrewave Radio Telescope (GMRT) and discovered the existence of a giant radio bridge connecting two pre-merging galaxy clusters A1758N and A1758S that are ~ 2 Mpc apart. This is the second large-scale radio bridge observed to date in a cluster pair. By studying the radio and X-ray emissions from the radio bridge, the astronomers found clear-cut evidence that the non-thermal phenomena in the intracluster medium (ICM) can be produced in the region of compressed gas in-between infalling systems. Cluster Merger: Galaxy Clusters Caught in a First Kiss. Source: Chandra The existence of radio bridges connecting pre-merging galaxy clusters has been confirmed very recently. Hitherto, only two such systems, namely A1758N-A1758S situated at a redshift of z ...

There may be a tiny black hole lurking in our Solar System

Astronomers J. Scholtz and J. Unwin in a new study investigated the anomalous orbits of trans-Neptunian objects (TNOs) and excess in microlensing events using the 5-year Optical Gravitational Lensing Experiment (OGLE) and came to the conclusion that these gravitational anomalies can be explained if a tiny primordial black hole with a mass few times that of the Earth were to be lurking in the outskirts of the Solar System. According to the leading Planet 9 hypothesis, it is believed that a super Earth-sized rogue planet must be present to shepherd the orbits of the TNOs. However, the new study suggested that the probability of the Sun capturing a primordial black hole is comparable to the capturing of a rogue planet and suggested ways by which the scenario could be verified or falsified. An Artist's illustration of the Solar system. Credit: pixel4k Until now, two distinct but seemingly interconnected gravitational anomalies have been detected with no consensus reg...

What is the largest structure in the Universe?

Have you ever wondered what is the biggest structure in our Universe? Well, the answer is the Hercules–Corona Borealis Great Wall. It's so massive that it takes light approximately 10 billion (10,000,000,000) years to cross it. It was first detected in 2013 by a team of astronomers while analyzing data from the Swift Gamma-Ray Burst Mission, together with other data from ground-based telescopes. Now, a new study using advanced statistical tools offered arguments that suggest that the structure may not be real and speculated about its potential origin. This enormous image shows Hubble’s view of the massive galaxy cluster MACS J0717.5+3745. Credit: NASA, ESA, Harald Ebeling (the University of Hawaii at Manoa) & Jean-Paul Kneib (LAM) The Hercules–Corona Borealis Great Wall is by far the largest structure in the observable Universe inferred from the clustering of gamma-ray bursts. The length of this structure is roughly 10% of the entire Universe. The structure lies in ...

Discovery of six galaxies powered by one supermassive black hole

A team of astronomers made a groundbreaking discovery of six closely bound galaxies being powered by a single supermassive black hole with a mass greater than a billion solar masses at a redshift of 6.31. Out of the six galaxies, four are massive star-forming galaxies and the other two are comparatively low mass galaxies. This is the first discovery of a galactic overdensity around a supermassive black hole in the first billion years of the Universe and confirms the idea that the most distant and massive black holes form and grow within massive dark matter halos in large scale structures. MS 0735.6+7421: Six objects ranging in location from within the Milky Way to billions of light-years away: Source: Chandra One of the major challenges in astronomy is to explain the existence of supermassive black holes powering luminous quasars at high redshifts. A quasar is an extremely bright active galactic nucleus fueled by a supermassive black hole. Quasars are typical of the size of...

New study says stellar mass of galaxies does not contain all the information about other galactic properties, refuting a major presumption in astronomy

Cosmologists from Visva-Bharati University and Osmania University reported that the stellar mass of galaxies does not encode all of the information about other galactic properties, an assumption long thought to be true. The new study used archival data from the SDSS in conjunction with cosmological simulations to come to this groundbreaking conclusion. An artist’s impression of the Milky Way galaxy. Photograph: Chen Xiaodian. Downloaded from: The Guardian Understanding the formation and evolution of galaxies is undoubtedly one of the major goals of modern cosmology. The integrated stellar mass of a galaxy is thought to be the most fundamental property which largely influences its structure and evolution. It is often taken as an impression of its formation h...

Huge exoplanet discovered orbiting a nearby star

A team of astronomers has discovered a new exoplanet named TOI-824 b orbiting a nearby star TOI-824 which is only 208 light-years away from us. The planet is massive in size with a mass equivalent to almost 19 times that of the Earth and has a radius equal to 3 times that of the Earth. The planet has an orbital period of 1.393 days and has a mean density of roughly 4 gm/cc making it more than twice as dense as Neptune. The discovery was made using data from the Transiting Exoplanet Survey Satellite (TESS). An artist’s impression of an exoplanet. Source: Alpha Coders As the name suggests, an exoplanet is a planet outside the solar system. The first confirmed detection of an exoplanet was made in 1992 by astronomers Aleksander Wolszczan and Dale Frail. On 6 October 1995, Michel Mayor and Didier Queloz discovered the first exoplanet orbiting a Sun-like star. This discovery was groundbreaking and opened...

Discovery of the first asteroid near Venus

A large team of astronomers discovered the first asteroid inside the orbit of Venus using the Zwicky Transient Facility located at the Palomar Observatory in California, United States. The asteroid has been named 2020 AV2 and is roughly 2 km in size with an aphelion distance (i.e., the point in the orbit of an object where it is farthest from the Sun ) of 0.65 astronomical units. The discovery could very well indicate that there may be a yet undiscovered population of asteroid lying outside of the asteroid belt and if more such asteroids are discovered, currently favored asteroid population models may need to be adjusted. Image of the largest asteroid Ceres. Source Wikipedia As of this writing, almost all of 1 million known asteroids lie between the orbits of Mars and Jupiter with only a handful lying near the orbit of Earth. Many scientists argue that there must be another population of asteroids present near the orbit of Venus. However, no such ast...

Spectacular discovery of the first Intermediate mass black hole through gravitational waves

On May 21, 2019, at 03:02:29 UTC the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaboration observed a short duration of the gravitational-wave signal, named GW190521. The detected signal is consistent with the merger of two black holes with masses of 85 and 66 solar masses. The mass of the remnant black hole is estimated to be around 142 solar masses, which makes the historic event GW190521 the first observational confirmation for the existence of an intermediate-mass black hole (IMBH). Artist's impression of binary black holes about to collide. Source: Caltech Black holes can be grouped into 4 categories depending on their masses. Firstly, there are the supermassive black holes that reside exclusively at the heart of galaxies having masses in the range from a few million to billions of solar masses. Then there are the intermediate-mass black holes having masses between a hundred to a few thousands of solar masses. Next are ...

New study shed light on the nature of mysterious dark energy

A team of cosmologists compared the theoretical predictions of the maximal abundance of massive galaxies predicted in different dynamical dark energy (DDE) models at high redshifts z ≈ 4 − 7 with the observed abundance and derived constraints for the evolution of the dark energy equation of state parameter which is complementary to the existing probes. The study employed three different, independent probes, namely the luminous end of the stellar mass function at z ≥ 6, the spatial density of luminous galaxies detected in the submillimeter range at z = 4 − 5, and the rareness of the extreme hyperluminous infrared galaxy SPT031158 at z ≈ 7. The analysis excluded a significant fraction of parameter spaces for the DDE models but interestingly does not completely exclude the possibility that dark energy may be dynamical (i.e, changing with time). Deepest visible-light image of the Universe containing nearly 10000 galaxies. Source: Hubble According to our current understanding of...

Astronomers discovered an exoplanet orbiting a dead star

For the first time, a giant exoplanet has been discovered orbiting a dead star (which in this case happens to a white dwarf) every 1.4 days. The planet is roughly the same size as Jupiter and is no more than 14 times as massive and has an equilibrium temperature of 165 K. The mass of the white dwarf is approximately 0.5 solar masses and with the radius roughly 10% that of the Sun. The groundbreaking discovery demonstrated that giant planets can be scattered into tight orbits without being tidally disrupted, and motivates searches for smaller transiting planets around white dwarfs. NGC 2392: A planetary nebula, a phase that results when a star like the Sun becomes a red giant and sheds its outer layers. Source: Chandra Exoplanet research is clearly amongst the most interesting research topics in astronomy. With the advancement of high-quality telescopes and detectors, thousands of exoplanets have been discovered and the numbers are only projected to surge in the coming years. Norma...

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