http://hdl.handle.net/2248/2 Wed, 02 Sep 2026 11:14:59 GMT 2026-09-02T11:14:59Z http://hdl.handle.net/2248/9024 Estimation of the energy involved in a solar coronal mass ejection using spectroscopic observations in the 5303Å emission line Ramesh, R; Priyal, M; Singh, J; Sasikumar Raja, K; Mishra, Wageesh; Monstein, C While the amount of solar coronal energy flux leaving the "quiet" Sun, coronal holes, and active regions has been estimated by many, similar calculations for transients like coronal mass ejections (CMEs) based on observations are few. Using spectroscopic observations in the 5303 Å coronal emission line with the Visible Emission Line Coronagraph on board Aditya-L1, we report estimates of the Alfvén wave energy flux before and during a transient coronal dimming caused by a CME. Our analysis indicates that the coronal energy flux associated with the dimming is ≍7.3 × 105 erg cm−2 s−1, which is ≍7% of the typical energy loss of 107 erg cm−2 s−1 from an active region due to conduction, radiative, and solar wind fluxes. Open Access; Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Wed, 01 Jul 2026 00:00:00 GMT http://hdl.handle.net/2248/9024 2026-07-01T00:00:00Z http://hdl.handle.net/2248/9023 On the relationship between solar spicules and propagating coronal disturbances: The role of shocks Chaurasiya, Ravi; Srivastava, Sankalp; Chatterjee, Piyali; Dey, Sahel; Erdelyi, Robertus; Bayanna, A. R Spicules and propagating coronal disturbances (PCDs) are ubiquitous dynamic features of the solar atmosphere, yet their physical connection remains an open question of paramount importance to the mass and energy transport in the solar atmosphere. Using concurrent multiwavelength high-resolution observations from the Swedish 1 m Solar Telescope and the Solar Dynamics Observatory, supported by two-dimensional radiative magnetohydrodynamic (MHD) simulations, we find that (i) shock waves in the chromosphere generated from nonlinear wave steepening drive some spicules, (ii) in the corona, these shock waves may transition into large amplitude nonlinear compressive MHD waves depending on the magnetic field strength and the ambient coronal conditions. In either case, the shocks or the large-amplitude compressive waves in the corona also transport mass flux upward and produce intensity variations in the form of PCDs in coronal passbands. Further, a multi-height wavelet analysis shows dominant ∼5 minute periods in the lower chromosphere that evolve into longer periods (≥10 minutes) at higher atmospheric layers, consistent with dispersive propagation in a stratified medium. The observational characteristics, together with the numerical simulations, demonstrate that a shock-driven MHD mechanism links spicule formation to coronal disturbances. Finally, mass flux estimates from both the observations and the simulations indicate that these PCDs can also aid in supplying mass to the solar wind. Open Access; Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Wed, 01 Jul 2026 00:00:00 GMT http://hdl.handle.net/2248/9023 2026-07-01T00:00:00Z http://hdl.handle.net/2248/9022 Subluminous type IIP SN 2024abfl as a result of a significantly low-energy Fe-core collapse Teja, Rishabh Singh; Sahu, D. K; Anupama, G. C; Singh, A; Dutta, Amrit; Rameshan, Gitika; Das, Hrishav; Kawabata, K. S; Singh, Mridweeka; Bhalerao, Varun We present extensive, well-sampled multiwavelength photometric and low-resolution optical spectroscopic observations of the low-luminosity Type IIP supernova (SN) SN 2024abfl. SN 2024abfl is found to be at the faintest end of Type IIP SNe with an unprecedented flat (0.1 mag 100 day─1) plateau evolution and a midplateau absolute magnitude of MV ≍ −13.8 mag, placing it among one of the faintest Type IIP SNe discovered to date. SN 2024abfl is adjacent to SN 2018zd in the same host NGC 2146. Using various SN distance measurement probes, we provide independent estimates of the debated distance to the host NGC 2146 (7─9 Mpc). The spectral evolution of SN 2024abfl is found to be similar to other SNe spectra of this subclass but with very narrow line profiles, indicating moderately low expansion velocities of the ejecta. Detailed 1D hydrodynamical modeling suggests a compact progenitor with an upper limit of 10 M⊙, fairly consistent with the directly detected progenitor estimates. It exploded with very low-energy 0.05 foe or less with a very low nickel mass of 0.003 M⊙, consistent with the observed parameters. These parameters provide important constraints on the nature of low-energy core-collapse explosions. We discuss possible progenitor scenarios and compare SN 2024abfl with other low-luminosity Type IIP SNe. Open Access; Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Wed, 01 Jul 2026 00:00:00 GMT http://hdl.handle.net/2248/9022 2026-07-01T00:00:00Z http://hdl.handle.net/2248/9021 BISTRO Survey: Gravity-dominated and magnetically regulated star formation in M17 SW Zhao, Mengke; Qiu, Keping; Kang, Ji-hyun; Tang, Xindi; Whitworth, Anthony; Ward-Thompson, Derek; Onaka, Takashi; Lee, Chang Won; Bourke, Tyler L; Hwang, Jihye; Eden, David; Hoang, Thiem; Tamura, Motohide; Kwon, Jungmi; Priestley, Felix; Kim, Kee-Tae; Arzoumanian, Doris; Francesco, James Di; Eswaraiah, Chakali; Johnstone, Doug; Nguyen, Bich Ngoc; Chen, Zhiwei; Sadavoy, Sarah; Archana Soam; Furuya, Ray; Lai, Shih-Ping; Kwon, Woojin; Bastien, Pierre; Pattle, Kate; Berry, David We present high-resolution magnetic field maps of the M17 SW molecular cloud using JCMT 850 μm dust polarization at scale of 14″. The magnetic field exhibits a distinct arc-like structure that encircles three dense clumps (C1, C2, and C3). By combining polarization data with ammonia line observations, the plane-of-sky magnetic field strength, measured using the Skalidis─Tassis method to minimize angle dispersion errors, ranges from 0.1 to 2.4 mG (mean: 0.54 mG). Energy budget analysis reveals a hierarchy dominated by gravity (eG ≍ 10−7.8 erg cm−3), which exceeds both magnetic (eB ≍ 10−8.3 erg cm−3) and turbulent (ek ≍ 10−8.7 erg cm−3) energies. Since all three energy densities lie within 1 order of magnitude, gravitational dominance acts primarily as the global driver, while the system remains in a state of near equipartition. Structurally, the northeastern boundary shows magnetic field lines perpendicular to the shock front, consistent with compression from the adjacent H II region. Within the cloud, magnetic field lines generally align with gravity to assist collapse, but turn perpendicular to gravity within curved accretion bridges. This configuration provides support against radial collapse while guiding gas flow. Kinematic evidence suggests that these channels transport material from clump C3 onto the massive clump C2. Star formation in M17 SW is globally driven by gravity but locally regulated by the magnetic field structure. Open Access; Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Wed, 01 Jul 2026 00:00:00 GMT http://hdl.handle.net/2248/9021 2026-07-01T00:00:00Z