Saraswati Supercluster

The Saraswati Supercluster[1][2] is a massive galaxy supercluster about 1.2 gigaparsecs (4 billion light years) away within the Stripe 82 region of SDSS, in the direction of the constellation Pisces.[3][4] It is one of the largest structures found in the universe, with a major axis in diameter of about 200 Mpc (652 million light years). It consists of at least 43 galaxy clusters, and has the mass of 2 × 10¹⁶ M_☉, forming a galaxy filament.[5]

Saraswati Supercluster
Axonometric representation of the Saraswati Supercluster Credit: Pablo Carlos Budassi
Observation data (Epoch J2000.0)
Constellation(s)	Pisces
Right ascension	23^h 37^m 40^s
Declination	00° 16′ 17″
Number of galaxies	43
Major axis	200 Mpc (652 Mly)
Redshift	0.28
Distance (co-moving)	1.2 Gpc (4 Gly)
Binding mass	2.0×10^16 M☉

Discovery

The Saraswati supercluster was discovered by a team of astrophysicists from the Inter-University Centre for Astronomy and Astrophysics and Indian Institute of Science Education and Research led by Prof Joydeep Bagchi and colleagues in Pune, India. A large part of Dr. Shishir Sankhyayan's PhD thesis work was dedicated for research on the Saraswati Supercluster. Other researchers part of this work are Dr Prakash Sarkar, Prof Somak Raychaudhury, Prof Joe Jacob and PhD research scholar Mr Pratik Dabhade. Analyzing the data of Stripe 82 of the comprehensive Sloan Digital Sky Survey, particularly the sets of LOWZ data from the Baryon Oscillation Spectroscopic Survey, part of the DR12 catalogue of the SDSS, the team discovered an overdensity of the sampled 625 galaxies from LOWZ and 3,016 from the LEGACY-BOSS-SOUTHERN, a survey of the southern sky that is also a part of SDSS DR12. It was discovered in 2017.[6][3]

Cosmology

The Saraswati Supercluster is one of the largest and most massive superclusters known, comparable to the massive Shapley Concentration in the nearby universe. The supercluster consists of 43 massive galaxy clusters, which include Abell 2361 and ZWCl 2341.1+0000. It is surrounded by a network of galaxy filaments, clusters, and voids.

The Saraswati supercluster and its environs reveal that some extreme large-scale, prominent matter density enhancements had formed in the past when dark energy had just started to dominate structure formation. This galactic concentration sheds light on the role of dark energy and cosmological initial conditions in supercluster formation.[7][8]

References

1. Karouzos, Marios (September 2017). "Saraswati the wide-reaching". Nature Astronomy. 1 (9): 564. Bibcode:2017NatAs...1..564K. doi:10.1038/s41550-017-0227-9. S2CID 126174348.
2. http://www.iucaa.in/~joydeep/saraswati.html
3. Bagchi, Joydeep; Sankhyayan, Shishir; Sarkar, Prakash; Raychaudhury, Somak; Jacob, Joe; Dabhade, Pratik (2017). "Saraswati: An Extremely Massive ~ 200 Megaparsec Scale Supercluster". The Astrophysical Journal. 844 (1): 25. arXiv:1707.03082. Bibcode:2017ApJ...844...25B. doi:10.3847/1538-4357/aa7949. S2CID 119360128.
4. "Descubierta Sarasvati, una de las mayores estructuras del universo" (in Spanish). El País. 14 July 2017. Retrieved 14 July 2017.
5. ""Saraswati"- one of the most massive large-scale structures in the Universe discovered". IUCAA. Archived from the original on 29 July 2017. Retrieved 14 July 2017.
6. https://www.youtube.com/watch?v=3v1FRDDy49E
7. Crane, Leah (14 July 2017). "Galaxy supercluster is one of the biggest things in the universe". NewScientist. Archived from the original on 8 October 2017. Retrieved 12 January 2018.
8. "'Saraswati': A Supercluster Of Galaxies Discovered By Indian Scientists". HuffingtonPost. 14 July 2017. Archived from the original on 14 July 2017. Retrieved 12 January 2018.