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Formation and Eruption of Filament Channel in Solar Active Region 12975: Insights from Observations and Simulations of Magnetic Field Evolution
Dinesh Mishra, P. Vemareddy, Brajesh Kumar
We studied the magnetic field evolution of active region (AR) 12975 using a time-dependent magnetofrictional (TMF) model. This AR produced two consecutive CMEs associated with M-cl…
On the propagation of gravity waves in the lower solar atmosphere in different magnetic configurations
Hirdesh Kumar, Brajesh Kumar, S. P. Rajaguru
Gravity waves are generated by turbulent subsurface convection overshooting or penetrating locally into a stably stratified medium. While propagating energy upwards, their characte…
A study of the propagation of magnetoacoustic waves in small-scale magnetic fields using solar photospheric and chromospheric Dopplergrams: HMI/SDO and MAST observations
Hirdesh Kumar, Brajesh Kumar, S. P. Rajaguru +2
In this work, we present a study of the propagation of low-frequency magneto-acoustic waves into the solar chromosphere within small-scale inclined magnetic fields over a quiet-mag…
First Lunar Occultation Results with the TIRCAM2 Near-Infrared Imager at the Devasthal 3.6-m Telescope
Saurabh Sharma, Andrea Richichi, Devendra K. Ojha +7
TIRCAM2 is the facility near-infrared Imager at the Devasthal 3.6-m telescope in northern India, equipped with an Aladdin III InSb array detector. We have pioneered the use of TIRC…
SN 2020sck: deflagration in a carbon-oxygen white dwarf
Anirban Dutta, D. K. Sahu, G. C. Anupama +7
We present optical UBVRI photometry and low-to-medium resolution spectroscopic observations of type Iax SN 2020sck spanning -5.5 d to +67 d from maximum light in the B-band. From t…
Differential rotation of the solar transition region from STEREO/EUVI 30.4 nm images
Jaidev Sharma, Brajesh Kumar, Anil K Malik +1
The solar photosphere, chromosphere and corona are known to rotate differentially as a function of latitude. To date, it is unclear if the solar transition region also rotates diff…
SN 2017hpa: A carbon-rich type Ia supernova
Anirban Dutta, Avinash Singh, G. C. Anupama +2
We present the optical (UBVRI) and ultraviolet (Swift-UVOT) photometry, and optical spectroscopy of Type Ia supernova SN 2017hpa. We study broadband UV+optical light curves and low…
Evidence of strong relationship between hemispheric asymmetry in solar coronal rotation and solar activity during solar cycle 24
Jaidev Sharma, Anil K Malik, Brajesh Kumar +1
In this article, we report an evidence of very high and statistically significant relationship between hemispheric asymmetry in solar coronal rotation rate and solar activity. Our…
On the seismic emission in sunspots associated with Lorentz force changes accompanying major solar flares
Hirdesh Kumar, Brajesh Kumar
Solar flares are known to generate seismic waves in the Sun. We present a detailed analysis of seismic emission in sunspots accompanying M- and X-class solar flares. For this purpo…
On the variation of solar coronal rotation using SDO/AIA observations
Jaidev Sharma, Brajesh Kumar, Anil K. Malik +1
We report on the variability of rotation periods of solar coronal layers with respect to temperature (or, height). For this purpose, we have used the observations from Atmospheric…
On the signatures of flare-induced global waves in the Sun: GOLF and VIRGO observations
Brajesh Kumar, Savita Mathur, Rafael A. Garcia +1
Recently, several efforts have been made to identify the seismic signatures of flares and magnetic activity in the Sun and Sun-like stars. In this work, we have analyzed the disk-i…
Analysis of sudden variations in photospheric magnetic fields during a large flare and their influences in the solar atmosphere
Brajesh Kumar, A. Raja Bayanna, P. Venkatakrishnan +1
The solar active region NOAA 11719 produced a large two-ribbon flare on 11 April 2013. We have investigated the sudden variations in the photospheric magnetic fields in this active…
Optical and NIR observations of the nearby type Ia supernova SN 2014J
Shubham Srivastav, J. P. Ninan, Brajesh Kumar +4
Optical and NIR observations of the type Ia supernova SN 2014J in M82 are presented. The observed light curves are found to be similar to normal SNe Ia, with a decline rate paramet…
A Study of the relation between intensity oscillations and magnetic field parameters in a Sunspot: Hinode Observations
Ankala Raja Bayanna, Shibu K Mathew, Brajesh Kumar +2
We present properties of intensity oscillations of a sunspot in the photosphere and chromosphere using G~band and CaIIH filtergrams from Hinode. Intensity power maps as function of…
Investigation of the stellar content in the western part of the Carina nebula
Brajesh Kumar, Saurabh Sharma, Jean Manfroid +4
We obtained deep H photometric data of the field situated to the west of the main Carina nebula and centered on WR~22. Medium-resolution optical spectroscopy of a subsam…
Main-sequence variable stars in young open cluster NGC 1893
Sneh Lata, Ram Kesh Yadav, A. K. Pandey +5
In this paper we present time series photometry of 104 variable stars in the cluster region NGC 1893. The association of the present variable candidates to the cluster NGC 1893 has…
On the line profile changes observed during the X2.2 class flare in the active region NOAA 11158
A. Raja Bayanna, Brajesh Kumar, P. Venkatakrishnan +4
The solar active region NOAA 11158 produced a series of flares during its passage through the solar disk. The first major flare (of class X2.2) of the current solar cycle occurred…
On the flare induced seismicity in the active region NOAA 10930 and related enhancement of global waves in the sun
Brajesh Kumar, P. Venkatakrishnan, Savita Mathur +2
A major flare (of class X3.4) occurred on 13 December 2006 in the active region NOAA 10930. The energy released during flares is also known to induce acoustic oscillations in the S…
SN 2008gz - most likely a normal type IIP event
Rupak Roy, Brijesh Kumar, Alexander S. Moskvitin +10
We present BV RI photometric and low-resolution spectroscopic investigation of a type II core-collapse supernova (SN) 2008gz, which occurred in a star forming arm and within a half…
Can major solar flares excite high-frequency global waves in the Sun ?
Brajesh Kumar, Savita Mathur, R. A. Garcia +1
The study of low-degree high-frequency waves in the Sun can provide new insight into the dynamics of the deeper layers of the Sun. Here, we present the analysis of the velocity obs…
On the flare induced high-frequency global waves in the Sun
Brajesh Kumar, Savita Mathur, R. A. Garcia +1
Recently, Karoff and Kjeldsen (2008) presented evidence of strong correlation between the energy in the high-frequency part (5.3<ν<8.3 mHz) of the acoustic spectrum of the Sun and…