Article
Astronomy & Astrophysics
Florian Niederhofer, Maria-Rosa L. Cioni, Stefano Rubele, Thomas Schmidt, Jonathan D. Diaz, Gal Matijevic, Kenji Bekki, Cameron P. M. Bell, Richard de Grijs, Dalal El Youssoufi, Valentin D. Ivanov, Joana M. Oliveira, Vincenzo Ripepi, Smitha Subramanian, Ning-Chen Sun, Jacco Th van Loon
Summary: This study utilized data from the VISTA survey to measure proper motions of stars within the SMC, finding that the galaxy may be experiencing stretching or stripping of its outer regions. The internal kinematics of young and old stellar populations were analyzed separately, revealing different motion patterns in different age groups.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Jonathan C. Bird, Sarah R. Loebman, David H. Weinberg, Alyson M. Brooks, Thomas R. Quinn, Charlotte R. Christensen
Summary: Kinematic studies of disc galaxies, using individual stars in the Milky Way or statistical studies of global disc kinematics over time, provide insights into how discs form and evolve. The key to success in understanding this process lies in the simulation's dynamically cold multiphase ISM, allowing young stars to form with low velocity dispersion. The evolution of disc galaxies is explained by a model where the decrease in velocity dispersion is due to a decreasing gas fraction over time, resulting in a quasi-stable equilibrium.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Cameron W. Trapp, Dusan Keres, Tsang Keung Chan, Ivanna Escala, Cameron Hummels, Philip F. Hopkins, Claude-Andre Faucher-Giguere, Norman Murray, Eliot Quataert, Andrew Wetzel
Summary: This study analyzes gas accretion in the vicinity of galaxies using the FIRE-2 cosmological zoom-in simulations. It finds that gas approaches the disc with low radial velocities and similar angular momentum to the gaseous disc edge, piling up near the edge and settling into full rotational support for star formation. The gas moves predominantly parallel to the disc and joins largely in the outskirts, with a brief period of more vertical trajectories before joining the disc. Within the disc, gas motion is complex, dominated by spiral arm induced oscillations and feedback.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Haiyang Yu, Ming Zhu, Jin-Long Xu, Mei Ai, Peng Jiang, Yanbin Yang
Summary: We observed the classical interacting galaxy M51 with FAST and obtained high-sensitivity H i image. Several new tidal features and a diffuse extended envelope around the system are observed. The Northwest Cloud appears to be the tail of M51a and the Northwest Plume is likely a tidal tail of M51b. The novel tidal features and probable gas of M51b will contribute to a deeper understanding of the system's evolution.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Tigran Khachaturyants, Leandro Beraldo e Silva, Victor P. Debattista
Summary: Recent studies have found star formation in the warp of the Milky Way, with these warp stars eventually settling into the disc. Research shows that warp stars first partially align with the main disc in about 1 Gyr, before phase mixing into an axisymmetric distribution over approximately 6 Gyr. The warp stars contribute to a negative vertical age gradient distribution and undergo radial migration toward the center of the galaxy.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Sarah A. Bird, Xiang-Xiang Xue, Chao Liu, Chris Flynn, Juntai Shen, Jie Wang, Chengqun Yang, Meng Zhai, Ling Zhu, Gang Zhao, Hai-Jun Tian
Summary: Using stellar halo samples, this study estimates the mass distribution and dark matter mass of the Milky Way through two methods. The results show reasonable consistency across different samples and methods.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
M. Yttergren, P. Misquitta, A. Sanchez-Monge, M. Valencia-S, A. Eckart, A. Zensus, T. Peitl-Thiesen
Summary: By studying Stephan's Quintet, we can gain insights into the complex processes of galaxy interactions and the evolution of structures in this galaxy group, providing a deeper understanding of the dynamics and physical processes at play in the nearby interactive group.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Anton V. Afanasiev, Igor Chilingarian, Kirill A. Grishin, Dmitry Makarov, Lidia Makarova, Daniel Fabricant, Nelson Caldwell, Sean Moran
Summary: Low-mass early-type galaxies, including dwarf spheroidals and brighter dwarf ellipticals, dominate the galaxy population in groups and clusters. Recently, an additional population of more extended ultradiffuse galaxies has been identified, sparking a discussion on the connections between the three classifications. The spatially resolved stellar kinematics of KDG 64 suggest it is a transitional object between dwarf spheroidals and ultradiffuse galaxies, with an old stellar population, no young stars, and a high dark matter mass fraction.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
B. Garcia-Conde, S. Roca-Fabrega, T. Antoja, P. Ramos, O. Valenzuela
Summary: The study focused on the vertical perturbations in the Milky Way-size high-resolution hydrodynamical cosmological simulation GARROTXA, identifying phase spirals in the vertical projection of the disc's stellar particles. The research suggests that mechanisms such as gas physics, collective effects of multiple perturbers, and dynamically cold populations play a role in the appearance of these structures. The use of fully cosmological simulations with high resolution can provide new insights into the nature and origin of phase spirals.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Giacomo Fragione, Rosalba Perna, Abraham Loeb
Summary: This paper discusses how tidal disruption events (TDEs) can offer a unique electromagnetic window into the assembly and merger of binary stellar-mass black holes and intermediate-mass black holes in nuclear star clusters. The predicted rate of TDEs in each galaxy is around 10(-6) to 10(-7) per year. The light curve of TDEs in nuclear star clusters may be interrupted and modulated by the companion black hole in the binary system.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Eric P. Andersson, Florent Renaud, Oscar Agertz
Summary: The study suggests that runaway stars might contribute to the phenomenon of star formation in the outskirts of spiral galaxies, enabling the appearance of star formation in regions with extremely low gas surface densities.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
C. Buttitta, E. M. Corsini, V. Cuomo, J. A. L. Aguerri, L. Coccato, L. Costantin, E. Dalla Bonta, V. P. Debattista, E. Iodice, J. Mendez-Abreu, L. Morelli, A. Pizzella
Summary: This study characterized the properties of the bar in the lenticular galaxy NGC4277 located behind the Virgo cluster, revealing that it hosts a short, weak, and slow bar with a pattern speed of 24.7 km s(-1) kpc(-1), amongst the best-constrained ones ever obtained with the TW method.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
C. Buttitta, E. M. Corsini, V. Cuomo, J. A. L. Aguerri, L. Coccato, L. Costantin, E. Dalla Bonta, V. P. Debattista, E. Iodice, J. Mendez-Abreu, L. Morelli, A. Pizzella
Summary: This study investigates the properties and formation mechanism of the bar hosted in the lenticular galaxy NGC 4277, located behind the Virgo cluster. The analysis of observational data reveals the presence of a short, weak, and slow bar in NGC 4277, with the measurement results being relatively accurate. NGC 4277 may be the first galaxy in which a slow-paced stellar bar is measured using a model-independent method.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
A. Bik, G. Ostlin, M. Hayes, J. Melinder, V Menacho
Summary: This study investigates the kinematics of nearby starburst galaxies selected from SDSS data. The results show a correlation between the rotational velocity and velocity dispersion of the gas and stellar components, and propose a scenario where gravitational instabilities determine the global kinematics of galaxies. The study highlights the importance of understanding the physics and assembly history of galaxies.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Caro Derkenne, Richard M. McDermid, Adriano Poci, J. Trevor Mendel, Francesco D'Eugenio, Seyoung Jeon, Rhea-Silvia Remus, Sabine Bellstedt, Andrew J. Battisti, Joss Bland-Hawthorn, Anna Ferre-Mateu, Caroline Foster, K. E. Harborne, Claudia D. P. Lagos, Yingjie Peng, Piyush Sharda, Gauri Sharma, Sarah Sweet, Kim-Vy H. Tran, Lucas M. Valenzuela, Sam Vaughan, Emily Wisnioski, Sukyoung K. Yi
Summary: We investigate the impact of environment on the internal mass distribution of galaxies using the MAGPI survey. We find that galaxies in high density clusters have less centrally concentrated mass distribution compared to galaxies in low-to-mid density environments. Our results suggest that environment plays a role in the internal mass distribution of galaxies, with no evolution of the slope in the last 3-4 Gyr.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Kaushar Vaidya, Anju Panthi, Manan Agarwal, Sindhu Pandey, Khushboo K. Rao, Vikrant Jadhav, Annapurni Subramaniam
Summary: In this study, we analyzed the blue straggler stars (BSS) in the NGC 7789 cluster using UVIT/AstroSat data and identified hot companions in 5 BSS candidates, confirming them as extremely low-mass white dwarfs formed through mass transfer.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
G. C. Anupama, G. Maheswar, S. Sriram, T. Sivarani, P. S. Parihar, S. Nagabhushan, Dorje Angchuk, S. Barway, B. C. Bhatt, R. Banyal, Alikhan Basheer, Prasanna Deshmukh, Devika Divakar, Tsewang Dorjai, Aruna Goswami, K. Govinda, Sonam Jorphail, U. S. Kamath, Madan Mohan Kemkar, Tashi Tsering Mahay, S. Muneer, C. Muthumariappan, Shantikumar Singh Ningombam, G. Pandey, B. E. Reddy, D. K. Sahu, D. S. Sandeep, Ramya Sethuram, C. S. Stalin, S. Subramanian, Stanzin Tsewang, A. Subramaniam
Summary: This article provides a brief description of the science cases that drive the telescope requirements, activities related to optics design and some thoughts on the instruments.
JOURNAL OF ASTROPHYSICS AND ASTRONOMY
(2022)
Article
Astronomy & Astrophysics
Arvind K. K. Dattatrey, R. K. S. Yadav, Sharmila Rani, Annapurni Subramaniam, Gaurav Singh, Snehalata Sahu, Ravi S. S. Singh
Summary: We report the discovery of extremely low mass white dwarfs (ELM WDs) as companions to blue straggler stars (BSSs) in the globular cluster NGC 362. By analyzing spectral energy distributions and fitting single or double-SEDs, we identified ELM WDs as binary companions in 12 out of 26 BSSs studied. The properties of the 12 ELM WDs suggest that they are formed through the case A/B mass transfer pathway.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
K. George, B. M. Poggianti, N. Tomicic, J. Postma, P. Cote, J. Fritz, S. K. Ghosh, M. Gullieuszik, J. B. Hutchings, A. Moretti, A. Omizzolo, M. Radovich, P. Sreekumar, A. Subramaniam, S. N. Tandon, B. Vulcani
Summary: Spiral galaxies experience strong ram-pressure effects when entering galaxy clusters, resulting in gas stripping and the formation of extended tails with jellyfish-like appearance. Ultraviolet observations of jellyfish galaxies JW39, JO60, and JO194 reveal star formation knots in the disc and tails, with strong correlation between their UV and H alpha flux. Optical emission line ratio maps identify emission mechanisms (star formation, LINER, or mix) in different regions, with star-forming regions matching regions with significant UV flux.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Sharmila Rani, Gajendra Pandey, Annapurni Subramaniam, N. Kameswara Rao
Summary: We present the first far-UV (FUV) imaging results of the NGC 2818 open cluster, which contains a planetary nebula (PN). By combining UVIT and Gaia EDR3 data, we identify cluster members and detect bright blue straggler stars (BSSs) and yellow straggler stars (YSSs). The BSSs are believed to be collisional products or have undetectable white dwarf (WD) companions, while the YSSs are formed through mass-transfer scenarios and likely consist of A-type subdwarfs. The presence of the planetary nebula in NGC 2818 provides an opportunity to test stellar evolution models.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Ranjan Kumar, Ananta C. Pradhan, Snehalata Sahu, Annapurni Subramaniam, Sonika Piridi, Santi Cassisi, Devendra K. Ojha
Summary: This study presents a study of hot stellar populations in globular clusters M3 and M13 using far-ultraviolet (FUV) observations. Based on the FUV-optical color-magnitude diagrams, the sources are classified into different types of stars. The comparison of synthetic and observed colors suggests that the mass-loss and helium spread have an effect on the different distributions of stars in the clusters.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
R. Rakhi, Geethika Santhosh, Prajwel Joseph, Koshy George, Smitha Subramanian, Indulekha Kavila, J. Postma, Pierre-Alain Duc, Patrick Cote, Luca Cortese, S. K. Ghosh, Annapurni Subramaniam, Shyam Tandon, John Hutchings, P. Samuel Wesley, Aditya Bharadwaj, Neeran Niroula
Summary: NGC 5291 is an early-type galaxy surrounded by a giant H I ring, which is believed to have been formed from collision with another galaxy. This collisional ring contains several star forming complexes and tidal dwarf galaxies, serving as sites of star formation in extreme dynamical environments. Using high spatial resolution FUV and NUV imaging observations, the star formation activity in the NGC 5291 system was studied and quantified, with the estimation of the total star formation rate.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Vikrant V. Jadhav, Annapurni Subramaniam, Ram Sagar
Summary: This study aims to detect the UV-bright population of NGC 6791 using AstroSat /UVIT images and characterize known post-mass-transfer systems. By analyzing spectral energy distribution, 20 members with large UV flux were identified, including five hot subdwarfs. Additionally, 10 extremely low-mass white dwarf candidates were detected hidden among other cluster members. This dynamically old open cluster is unique and serves as an ideal test bed for dynamical studies.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Nagaraj Vernekar, Annapurni Subramaniam, Vikrant V. Jadhav, Dominic M. Bowman
Summary: Blue straggler stars (BSSs) with white dwarf (WD) companions were observed in M67, indicating a mass transfer pathway of formation. Light curves from K2 and TESS data were analyzed to study five BSSs in M67 that are known to be spectroscopic binaries. Variability was detected in WOCS 1007, with the light curve dominated by ellipsoidal variation. Its companion was estimated to be a low-mass WD with an orbital period of 4.212 & PLUSMN; 0.041 d. Other BSSs showed no eclipses or pulsations, confirming the absence of high inclination inner binaries.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Anju Panthi, Annapurni Subramaniam, Kaushar Vaidya, Vikrant Jadhav, Sharmila Rani, Sivarani Thirupathi, Sindhu Pandey
Summary: The study reports the discovery of white dwarf companions of 12 blue metal-poor stars using UVIT/AstroSat observations. The analysis shows that these companion stars have a wide range of masses and belong to different stellar populations. The results suggest that at least 44% of the blue metal-poor stars are formed through mass transfer, providing important insights into the process of mass transfer and binary properties among these stars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
S. Sriram, Vineeth Valsan, A. Subramaniam, C. Vishnu Unni, G. Maheswar, Totan Chand
Summary: Large ground and space-based surveys in optical and near-infrared wavelengths are planned for the next decade, but there are no UV facilities planned to complement these surveys. To observe the UV sky and study active phenomena in the Universe, a dedicated UV mission called INSIST is proposed. Through a trade study, the most optimal optical design for INSIST was selected.
JOURNAL OF ASTROPHYSICS AND ASTRONOMY
(2023)
Article
Astronomy & Astrophysics
Gourav Banerjee, Blesson Mathew, K. T. Paul, Annapurni Subramaniam, Anjusha Balan, Suman Bhattacharyya, R. Anusha, Deeja Moosa, C. S. Dheeraj, Aleeda Charly, Megha Raghu
Summary: The variability of classical Be stars is a common property. By studying the H alpha line profiles, the disc-loss and reappearing phases of CBe stars can be identified. This research on nine bright CBe stars helps to better understand their disc transient nature and classify them into growing, stable, and dissipating disc groups based on the variations in the H alpha EW.
JOURNAL OF ASTROPHYSICS AND ASTRONOMY
(2022)
Article
Astronomy & Astrophysics
Thirupathi Sivarani, Ramya Sethuram, S. Sriram, Devika Divakar, Arun Surya, Hari Mohan Varshney, Sudarshan Kambala, Amirul Hasan, Ajin Prakash, K. V. Govinda, Viswanatha, G. C. Anupama, G. Maheswar, D. Ojha, S. B. Pandey, J. Pandey, M. Puravankara, A. N. Ramaprakash, B. E. Reddy, Sarang S. Shah, R. Srianand, A. Subramaniam, S. Subramanian
Summary: The future of astronomy will be shaped by the upcoming three extremely large optical telescopes, the TMT, GMT, and ELT. These telescopes have been identified as top priorities for ground-based astronomy by the US and Canada. India is a partner in the TMT and has made significant contributions to its development.
JOURNAL OF ASTROPHYSICS AND ASTRONOMY
(2022)
Article
Astronomy & Astrophysics
Annapurni Subramaniam
Summary: India achieved a significant milestone in space astronomy with the successful launch of AstroSat. They are now planning to expand their presence in the international space astronomy community with the proposal of a next generation UV-optical mission, INSIST, which aims to produce high-quality imaging and spectra. The mission's main scientific drivers cover a wide range of topics including galaxy evolution, cosmology, and stellar systems.
JOURNAL OF ASTROPHYSICS AND ASTRONOMY
(2022)
Proceedings Paper
Astronomy & Astrophysics
Sarang Shaha, Smitha Subramanian, G. C. Anupama, Francisco Delgado, Kim Gillies, Maheshwar Gopinathan, Rajalakshmi Narayanan, A. N. Ramaprakash, Suhasini Rao, B. E. Reddy, Warren Skidmore, T. Sivarani, Annapurni Subramaniam
Summary: This paper presents a roadmap for generating an Infrared Guide Star Catalogue (IRGSC) for TMT. The catalogue is crucial for the efficient operation of NFIRAOS, which assists the NIR instruments of TMT. The authors use optical data from Pan-STARRS observations and compute the NIR magnitudes of stellar sources by employing stellar atmospheric models and Spectral Energy Distribution (SED) fits.
ADAPTIVE OPTICS SYSTEMS VIII
(2022)