IIA Institutional Repository: Recent submissions

  • The role of magnetic fields in the stability and fragmentation of filamentary molecular clouds: two case studies at OMC-3 and OMC-4 
    Li, Pak Shing; Lopez-Rodriguez, Enrique; Archana Soam; Klein, Richard I (Oxford University Press on behalf of Royal Astronomical Society, 2022-08)
    We present the stability analysis of two regions, OMC-3 and OMC-4, in the massive and long molecular cloud complex of Orion A. We obtained 214 μm HAWC + /SOFIA polarization data, and we make use of archival data for the ...
  • Spectroscopic Study of Four Metal-poor Carbon Stars from the Hamburg/ESO Survey: On Confirming the Low-mass Nature of Their Companions* 
    Shejeelammal, J; Goswami, A (American Astronomical Society, 2022-08-01)
    Elemental abundances of extrinsic carbon stars provide insight into the poorly understood origin and evolution of elements in the early Galaxy. In this work, we present the results of a detailed spectroscopic analysis of ...
  • The X-Ray and Radio Loud Fast Blue Optical Transient AT2020mrf: Implications for an Emerging Class of Engine-driven Massive Star Explosions 
    Yao, Yuhan; Ho, Anna Y. Q; Medvedev, Pavel; Nayana, A. J; Perley, Daniel A; Kulkarni, S. R; Chandra, Poonam; Sazonov, Sergey; Gilfanov, Marat; Khorunzhev, Georgii; Khatami, David K; Sunyaev, Rashid (American Astronomical Society, 2022-08-01)
    We present AT2020mrf (SRGe J154754.2+443907), an extra-galactic (z = 0.1353) fast blue optical transient (FBOT) with a rise time of tg,rise = 3.7 days and a peak luminosity of Mg,peak = −20.0. Its optical spectrum ...
  • Nature of helicity injection in non-erupting solar active regions 
    Vemareddy, P (Oxford University Press on behalf of Royal Astronomical Society, 2022-10)
    Using time-sequence vector magnetic field and coronal observations from Solar Dynamics Observatory, we report the observations of the magnetic field evolution and coronal activity in four emerging active regions (ARs). ...
  • Characterizing Solar Eruptions in Inner Corona using Ground and Space-based Data 
    Ritesh, Patel (Indian Institute of Astrophysics, 2021-08)
    The solar corona is known to be associated with eruptions of large amount of magnetized plasma into the interplanetary space. In-spite of several years of ground- and space-based observations of the solar atmosphere, the ...
  • Optimum design and development of segmented mirror telescope optics and phasing system 
    Jacob, A (Indian Institute of Astrophysics, 2020-10)
    Astronomy today is in the path of constructing large telescopes. Due to several manufacturing and maintenance difficulties, large telescopes of more than 8 m are predominantly segmented. To fulfill the need for its growing ...
  • Flux and spectral variability of Mrk 421 during its moderate activity state using NuSTAR: Possible accretion disc contribution? 
    Mondal, S; Priyanka Rani; Stalin, C. S; Chakrabarti, S. K; Rakshit, S (EDP Sciences, 2022-07)
    Context. The X-ray emission in BL Lac objects is believed to be dominated by synchrotron emission from their relativistic jets. However, when the jet emission is not strong, one could expect signatures of X-ray emission ...
  • Accretion disc sizes from continuum reverberation mapping of AGN selected from the ZTF survey 
    Jha, Vivek Kumar; Joshi, Ravi; Chand, Hum; Wu, Xue-Bing; Ho, Luis C; Rastogi, Shantanu; Ma, Qinchun (Oxford University Press on behalf of Royal Astronomical Society, 2022-04)
    We present the accretion disc-size estimates for a sample of 19 active galactic nuclei (AGNs) using the optical g-, r-, and i-band light curves obtained from the Zwicky Transient Facility survey. All the AGNs have reliable ...
  • Probing infrared excess connection with Li enhancement among red clump giants 
    Mallick, Anohita; Reddy, B. E; Muthumariappan, C (Oxford University Press on behalf of Royal Astronomical Society, 2022-04)
    We have performed a search among low-mass red giants for finding evidence for merger scenario for triggering He-flash and subsequent Li enhancement. We chose a sample of red giants from GALAH survey with well-measured Li ...
  • Quasi-periodic spicule-like cool jets driven by Alfvén pulses 
    Singh, B; Srivastava, A. K; Sharma, K; Mishra, S. K; Dwivedi, B. N (Oxford University Press on behalf of Royal Astronomical Society, 2022-04)
    We perform a 2.5D magnetohydrodynamic simulation to gain a comprehensive understanding of the formation of spicule-like cool jets caused by initial transverse velocity pulses akin to Alfven´ pulses in the solar chromosphere. ...
  • Formation and Abundance of Late-forming Primordial Black Holes as Dark Matter 
    Chakraborty, Amlan; Chanda, Prolay K; Pandey, Kanhaiya L; Das, Subinoy (American Astronomical Society, 2022-06-20)
    We propose a novel mechanism where primordial black hole (PBH) dark matter is formed much later in the history of the universe, between the epochs of Big Bang nucleosynthesis and cosmic microwave background photon decoupling. ...
  • Circular Polarization Observations of Type II Solar Radio Bursts and the Coronal Magnetic Field 
    Ramesh, R; Kathiravan, C; Ebenezer, E (American Astronomical Society, 2022-06-10)
    It is well known that magnetic field strength (B) in the solar corona can be calculated using the Alfvén Mach number (MA) and Alfvén speed (vA) of the magnetohydrodynamic shock waves associated with coronal type II radio ...
  • In Search of Short Gamma-Ray Burst Optical Counterparts with the Zwicky Transient Facility 
    Ahumada, Tomás; Anand, Shreya; Coughlin, Michael W; Andreoni, Igor; Kool, Erik C; Kumar, Harsh; Reusch, Simeon; Sagués-Carracedo, Ana; Stein, Robert; Cenko, Bradley S; Kasliwal, Mansi M; Singer, Leo P; Dunwoody, Rachel; Mangan, Joseph; Bhalerao, Varun; Bulla, Mattia; Burns, Eric; Graham, Matthew J; Kaplan, David L; Perley, Daniel; Almualla, Mouza; Bloom, Joshua S; Cunningham, Virginia; De, Kishalay; Gatkine, Pradip; Ho, Anna Y. Q; Karambelkar, Viraj; Kong, Albert K. H; Yao, Yuhan; Anupama, G. C; Barway, Sudhanshu; Ghosh, Shaon; Itoh, Ryosuke; McBreen, Sheila; Bellm, Eric C; Fremling, Christoffer; Laher, Russ R; Mahabal, Ashish A; Riddle, Reed L; Rosnet, Philippe; Rusholme, Ben; Smith, Roger; Sollerman, Jesper; Bissaldi, Elisabetta; Fletcher, Corinne; Hamburg, Rachel; Mailyan, Bagrat; Malacaria, Christian; Roberts, Oliver (American Astronomical Society, 2022-06-10)
    The Fermi Gamma-ray Burst Monitor (GBM) triggers on-board in response to ∼40 short gamma-ray bursts (SGRBs) per year; however, their large localization regions have made the search for optical counterparts a challenging ...
  • NuSTAR spectral analysis of three Seyfert galaxies: NGC 3227, NGC 5548, and MR 2251−178 
    Pal, Indrani; Stalin, C. S; Mallick, L; Priyanka Rani (EDP Sciences, 2022-06)
    Context. The observed nuclear X-ray emission in the radio-quiet category of active galactic nuclei (AGN) is believed to be from a compact region, the corona, which is situated in the vicinity of central supermassive black ...
  • Variable mass accretion and failed wind explain changing-look phenomena in NGC 1365 
    Mondal, Santanu; Adhikari, T. P; Hryniewicz, K; Stalin, C. S; Pandey, Ashwani (EDP Sciences, 2022-06)
    Changing-look active galactic nuclei (CLAGNs) show a complex nature in their X-ray spectral shape and line-of-sight column-density variation. The physical mechanisms responsible for these variations are unclear. Here, we ...
  • The Solar Activity Monitor Network – SAMNet 
    Erdelyi, Robertus; Korsos, Marianna B; Huang, Xin; Yang, Yong; Pizzey, Danielle; Wrathmall, Steven A; Hughes, Ifan G; Dyer, Martin J; Dhillon, Vikram S; Belucz, Bernadett; Brajsa, Roman; Chatterjee, Piyali; Cheng, Xuewu; Deng, Yuanyong; Dominguez, Santiago Vargas; Joya, Raul; Gömöry, Peter; Gyenge, Norbert G; Hanslmeier, Arnold; Kucera, Ales; Kuridze, David; Li, Faquan; Liu, Zhong; Xu, Long; Mathioudakis, Mihalis; Matthews, Sarah; McAteer, James R.T; Pevtsov, Alexei A; Pötzi, Werner; Romano, Paolo; Shen, Jinhua; Temesvary, Janos; Tlatov, Andrey G; Triana, Charles; Utz, Dominik; Veronig, Astrid M; Wang, Yuming; Yan, Yihua; Zaqarashvili, Teimuraz; Zuccarello, Francesca (EDP Sciences, 2022-06)
    The Solar Activity Magnetic Monitor (SAMM) Network (SAMNet) is a future UK-led international network of ground-based solar telescope stations. SAMNet, at its full capacity, will continuously monitor the Sun’s intensity, ...
  • A 10-m class national large optical-IR telescope 
    Anupama, G. C; Maheswar, G; Sriram, S; Sivarani, T; Parihar, P. S; Nagabhushana, S; Angchuk, D; Barway, Sudhanshu; Bhatt, B. C; Banyal, R. K; Basheer, Alikhan; Prasanna, Deshmukh; Divakar, D. K; Dorjai, T; Goswami, A; Govinda, K. V; Jorphail, S; Kamath, U. S; Kemkar, P. M. M; Mahay, T. T; Muneer, S; Muthumariappan, C; Shantikumar, N. S; Pandey, G; Reddy, B. E; Sahu, D. K; Sandeep, D. S; Ramya, S; Stalin, C. S; Subramanian, S; Tsewang, Stanzin; Subramaniam, A (Indian Academy of Science, 2022-06)
    An observatory class national large optical-IR telescope (NLOT), is proposed to be built and located in the country. The telescope consists of a 10–12 m segmented primary. In order to cater to a diversity of observational ...
  • The twin radio galaxy TRG J104454+354055 
    Gopal-Krishna; Joshi, Ravi; Patra, Dusmanta; Yang, Xiaolong; Ho, Luis C; Wiita, Paul J; Omar, Amitesh (Oxford University Press on behalf of Royal Astronomical Society, 2022-07)
    We report observations of a bright dumb-bell system of galaxies (z = 0.162) with the upgraded Giant Metrewave Radio Telescope (uGMRT), which show that each member of this gravitationally bound pair of galaxies hosts bipolar ...
  • The Magnetic Field in the Milky Way Filamentary Bone G47 
    Stephens, Ian W; Myers, Philip C; Zucker, Catherine; Jackson, James M; Andersson, B.-G; Smith, Rowan; Archana Soam; Battersby, Cara; Sanhueza, Patricio; Hogge, Taylor; Smith, Howard A; Novak, Giles; Sadavoy, Sarah; Pillai, Thushara G.S; Li, Zhi-Yun; Looney, Leslie W; Sugitani, Koji; Coude, Simon; Guzman, Andres; Goodman, Alyssa; Kusune, Takayoshi; Santos, Fabio P; Zuckerman, Leah; Encalada, Frankie (IOP Publishing, 2022-02-10)
    Star formation primarily occurs in filaments where magnetic fields are expected to be dynamically important. The largest and densest filaments trace the spiral structure within galaxies. Over a dozen of these dense (∼104 ...
  • The long-active afterglow of GRB 210204A: detection of the most delayed flares in a gamma-ray burst 
    Kumar, Harsh; Gupta, Rahul; Saraogi, Divita; Ahumada, Tomás; Andreoni, Igor; Anupama, G. C; Aryan, Amar; Barway, Sudhanshu; Bhalerao, Varun; Chandra, Poonam; Coughlin, Michael W; Dimple; Dutta, Anirban; Ghosh, Ankur; Ho, Anna Y. Q; Kool, E. C; Kumar, Amit; Medford, Michael S; Misra, Kuntal; Pandey, Shashi B; Perley, Daniel A; Riddle, Reed; Ror, Amit Kumar; Setiadi, Jason M; Yao, Yuhan (Oxford University Press on behalf of Royal Astronomical Society, 2022-06)
    We present results from extensive broadband follow-up of GRB 210204A over the period of 30 d. We detect optical flares in the afterglow at 7.6 × 105 s and 1.1 × 106 s after the burst: the most delayed flaring ever detected ...

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