arXiv subjects

Kuntal Misra

Publications and source records attributed to Kuntal Misra.

At least 19 recordsLinked to original sources

arXiv2026

Demonstrating the Time-Domain Capabilities of the 4-m International Liquid Mirror Telescope: An Early Census of Transient and Variable Detections

The PyLMT transient detection pipeline has been operational since November 2023, detecting transient and variable objects in the ILMT images in almost real time. Using the image subtraction technique, nearly 3700 CCD frames have been analyzed by the automated pipeline, generating nearly 23,000 alerts for the detection of verified transient candidates and cataloged variable sources. Around 21,000 of the alerts correspond to known MPC asteroids, nearly 2000 correspond to variable stars (including eclipsing binaries, RR Lyrae, Delta Scuti, T-Tauri, etc.), 509 correspond to variable AGNs (including QSOs, Seyfert galaxies, and blazars), 21 supernova candidates, and several other interesting candidates. We provide a concise overview of the detections and their significance, emphasizing the surveys potential contributions to a broad class of astrophysical and scientific cases. A transient detection dashboard called DART was developed using Streamlit to visualize and categorize candidates based on PyLMT and SIMBAD classifications. It includes cone-search functionality and displays key metadata, offering an intuitive interface that is publicly accessible. Our results demonstrate the viability of liquid mirror telescopes such as the ILMT for time-domain astronomy, emphasizing the important role that small-field survey facilities can play in systematic transient science programs.

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arXiv2026

SN 2022xus: bridging the gap between Type IIP and IIL supernovae

We present optical photometric and spectroscopic observations of the Type~II supernova SN~2022xus. The SN reached its peak {\em V} band magnitude of $-16.32$ mag within $\sim$7 days of explosion, followed by a plateau phase lasting $\sim$94 days with a declination rate of $\sim$1.2 mag (100 day)$^{-1}$. Early time spectra exhibit broad features that could be caused by the blending of several high-ionisation lines, likely arising from a relatively weak interaction between the SN ejecta and the surrounding circumstellar medium (CSM). Compared to typical Type~IIP SNe, SN~2022xus exhibits a smaller H$\alpha$ absorption-to-emission ratio ($a/e$), indicating a relatively small hydrogen envelope mass at the time of explosion. From nebular-phase spectroscopy and bolometric light curve modelling, the progenitor mass is estimated to be in the range of 12 -- 15 M$_\odot$. The multi-band light curve modelling using \texttt{REDBACK} infers a similar progenitor mass, a low mass-loss rate, and a confined CSM. Although several photometric and spectroscopic characteristics place the SN within the Type~IIL population, it displays mixed properties of both Type~IIP and Type~IIL SNe and cannot be cleanly classified into either subclass. We therefore identify SN~2022xus as a transitional event between Type~IIP and Type~IIL SNe, providing further evidence for a continuum between these two classes.

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arXiv2026

Astrometric Calibration of the 4-m International Liquid Mirror Telescope Observations

The 4-m International Liquid Mirror Telescope (ILMT) is a dedicated time domain survey telescope that continuously scans the zenithal sky over the Indian Himalayas in the g', r' and i' optical bands. Its unique capability to repeatedly image the same strip of sky every night makes it a highly useful instrument for the photometric and astrometric studies of Solar System, Galactic and extragalactic objects. We present a robust astrometric calibration pipeline developed for the ILMT data obtained in the time delay integration (TDI) mode. The pipeline uses a linear transformation model from pixel to world coordinates, with a second order correction for the asymmetric optical distortions introduced by the telescope's optical corrector, and ties the astrometric solution to the Gaia DR3 reference frame. The pipeline is integrated to the routine ILMT data processing workflow. Using data from the first four observing cycles (2022-2025), we present the first assessment of the astrometric performance of the pipeline based on positional residuals of sources cross-matched with Gaia DR3. The pipeline achieves a typical astrometric precision of ~100 milliarcseconds (mas), reaching ~70-80 mas for moderately bright sources (G~16.5-18.5). These results, based on 347 nights of data, demonstrate the stability and reliability of ILMT astrometry over multi-year timescales. The astrometrically calibrated data from these four observing cycles have been made publicly available to the astronomical community. This work establishes a validated framework for precision astrometry with zenith-pointing TDI surveys and provides a foundation for future time-domain studies with ILMT, including variability characterization, transient localization, and long-term positional monitoring.

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arXiv2026

Detection and identification of asteroids with the 4-m ILMT

The International Liquid Mirror Telescope (ILMT) covers a 22.3' wide strip of sky in declination ({\delta}), centred at {\delta} = +29{\deg} 21' 41.4'' and right ascension ({\alpha}) in the range 0 h <= {\alpha} < 24 h. Having a short focal length (f /D ~ 2.4) and a large diameter (4 m), makes the ILMT an excellent asteroid hunter. The ILMT began its 4th cycle in October 2024, running through May 2025. The astrometric accuracy has been improved to 0.1'' , and the PyLMT - a detection and classification pipeline -, has been fine-tuned using data from previous cycles. The current detection rate is tens of transients detected each night with high accuracy in classification and identification. We present statistical results for the asteroids detected during ILMT's Cycles 1-4. We first evaluate the astrometric performance of the detections across different ecliptic latitude ranges. We then describe the positions, apparent motions, and V magnitudes predicted by the Minor Planet Center (MPC) for the asteroids observed in the SDSS g', r', and i' bands. Finally, we assess the ILMT's potential for detecting near-Earth objects (NEOs), potentially hazardous asteroids (PHAs), and comets.

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arXiv2026

SN 2024dy: Dust formation in a long-lived Type IIn supernova and constraints on the dust mass

Type~IIn supernovae (SNe) are a subclass of core-collapse SNe powered by interaction between the ejecta and the dense circumstellar material. Among them, long-lived Type~IIn events are characterized by luminous, long-duration light curves with high radiative energy. Several cases of long-lived type IIn SNe exhibit substantial dust emission at late times. However, well-observed examples remain limited, and the details of their dust formation mechanisms remain poorly understood. Here we present photometric and spectroscopic observations of the Type~IIn SN~2024dy in ultraviolet, optical, and near-infrared (NIR) wavelength for $500$ days. SN~2024dy reached a peak magnitude of $M_r=-19.2$~mag with a total radiation energy of $1.9\times10^{50}$~erg. A NIR excess emerged at late phases, and the spectral energy distribution modeling indicates the presence of carbon dust with temperatures of $1300$-$1800$~K and masses of about $10^{-5}\ M_\odot$. The spectra features were typical of long-lived Type~IIn SNe. The late time H$\alpha$ profile exhibits a strong suppression of the red wing, providing evidence for newly formed dust. Our results suggest that the derived dust mass above may be underestimated due to optical depth effects. SN~2024dy provides an important observational case for understanding dust formation in Type~IIn SNe.

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arXiv2026

Transfer learning for transient search with small-field optical survey telescopes

The advent of optical sky surveys has enabled several automated programs for searching transients. Many of these programs extensively use supervised machine learning (ML) algorithms to automate these searches. Effective implementation of such a strategy has an advantage over non-automated methods of transient search in terms of reduced manual labour and reporting latency. Training the relevant ML algorithms often requires extensive labelled training datasets that might not be readily available for new or small field-of-view survey telescopes. Transfer Learning (TL) is an ML technique that is often employed to address this issue by transferring knowledge from a pre-trained model, trained on an extensive dataset for a related task, to enhance performance on a new task with a limited dataset available. This paper demonstrates TL for a Convolutional Neural Network (CNN)-based real/bogus classifier model for transient detection between extensive publicly available image data from the Zwicky Transient Facility (ZTF) and a small and labelled dataset from the 4-m International Liquid Mirror Telescope (ILMT). The same technique was employed to train two different types of transient alert classifiers to characterise the detected candidates based on detection image stamps into 3 and 4 classes, respectively. The resulting model for the real/bogus classifier achieved an accuracy of 97.3% on the test dataset. Additionally, an accuracy of 92.9% was achieved for the 3-class classifier and 85.6% for the 4-class classifier. Furthermore, the statistical significance of the effectiveness of this technique was established with an unpaired t-test between TL models and baseline models trained without TL.

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arXiv2026

Failed jet breakout in the metal-poor broad-lined type Ic supernova 2026gzf

A long-standing question in the death of massive stars is the role of relativistic jets. While many gamma-ray bursts and some fast X-ray transients seem to be associated with broad-lined type Ic supernovae, the opposite is not true. The lack of observable jet emission in those Ic-BL SNe can be explained by invoking off-axis jets, choked jets that inject all their energy into the stellar envelope, baryon-loaded jets for which the prompt high-energy emission is strongly suppressed, or non-jetted SNe. The lack of exact explosion time in the majority of SNe presents an obstacle to distinguish between these scenarios. Here we report the properties of SN 2026gzf associated with the X-ray thermal Einstein Probe shock-breakout EP260321a at z=0.0343. The absence of compelling shocked cocoon and radio emission up to 54 days, combined with initial expansion velocities of ~30,000 km/s and a circumstellar shell of ~0.07 M$_\odot$, favour a scenario for SN 2026gzf in which a jet was choked in the circumstellar shell. Our high-spatial resolution images of the SN environment show that the progenitor was located between two highly star-forming regions with a metallicity lower than any previously known Ic-BL SN. As the first case of a Ic-BL SN associated with high-energy prompt emission without the signature of a jet, SN 2026gzf provides a unique perspective to understand the successful launch of relativistic jets during the deaths of massive stars.

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arXiv2026

Performance of the 4-m International Liquid Mirror Telescope tested in two fields at high and low ecliptic and galactic latitudes

The 4-m International Liquid Mirror Telescope (ILMT) offers a unique opportunity to detect transients in a narrow strip of sky. We explore ILMT's potential to detect astrometric and photometric transients at various ecliptic and galactic latitudes. We inspected CCD frames observed at both low and high ecliptic and galactic latitudes during the commissioning phase and the November 2023 - May 2024 observation cycle, respectively. We analysed these images using both visual inspection and the ILMT's transient detection and candidate classification pipeline. In the low ecliptic and galactic latitude field, we detected more than 500 transient candidates. We cross-matched these with the Minor Planet Checker (MPC) database, identifying 504 catalogued asteroids, all with predicted V-magnitudes brighter than 24 mag, representing a total of 152 distinct asteroids. We performed the same steps on the high ecliptic and galactic latitude field, detecting 30 MPC-catalogued asteroids, and one newly discovered photometric transient, named AT 2024fxn. We present the positions, trajectories, and magnitudes of the detected asteroids observed in the SDSS g', r', and i' spectral bands and compare results from both fields. We explore the lightcurve of AT 2024fxn, which shows partial compatibility with a supernova (SN) hypothesis, while the data invites further insights.

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arXiv2026

Abundance Stratification in Type Iax SN 2020rea with TARDIS

Using the 1D Monte Carlo-based radiative transfer code TARDIS, we investigate the spectral evolution of the Type Iax supernova (SN) 2020rea from -7 days before to +21 days after maximum light. Our best-fit models indicate stratified, velocity-dependent abundances at early times, successfully reproducing most observed spectral features. As the SN evolves, the ejecta transition from a layered to a more homogeneous composition, posing an alternative to pure deflagration models that predict fully mixed ejecta. These results highlight the need for further investigation, as current pure deflagration models cannot fully explain the origin or spectral properties of Type Iax SNe like SN 2020rea.

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arXiv2026

GRB 230204B: GIT Discovery of a Fast Fading Afterglow Associated with an Energetic GRB from a Massive-Star Progenitor

We present a comprehensive multi-wavelength study of a bright gamma-ray burst GRB 230204B, analyzing both prompt and afterglow emissions. This GRB is highly energetic, with an isotropic equivalent energy emission $E_{\mathrm{iso}} \sim 2.2 \times 10^{54}\ \mathrm{erg}$, released during the prompt emission. The GROWTH-India Telescope discovered a bright afterglow ($m_r = 15.55$) that faded rapidly ($\propto t^{-1.82}$). The prompt emission shows strong thermal photospheric emission, along with a non-thermal high-energy component. We explore the evolution of these components and find them to be consistent with theoretical expectations. Afterglow modeling reveals an energetic jet $E_{tot} \gtrsim 10^{52}\ \mathrm{erg}$ expanding into a wind-type medium viewed nearly on-axis, suggesting a massive star progenitor with strong winds. We also explore correlations between the prompt emission and afterglow that may help to understand the complete picture of GRB progenitors.

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arXiv2026

Photometry and Spectroscopy of SN 2024pxl: A Luminosity Link Among Type Iax Supernovae

We present extensive ultraviolet to optical photometric and optical to near-infrared (NIR) spectroscopic follow-up observations of the nearby intermediate-luminosity ($M_V = -16.81\pm0.19$~mag) Type Iax supernova (SN) 2024pxl in NGC 6384. SN~2024pxl exhibits a faster light curve than the high-luminosity members of this class, and slower than low-luminosity events. The observationally well-constrained rise time of $\sim$11 days and an estimated synthesized $^{56}$Ni mass of 0.03\, M$_\odot$, based on analytical modeling of the integrated spectral energy distribution light curve, are consistent with models of the weak deflagration of a carbon-oxygen white dwarf. Our optical spectral sequence of SN~2024pxl shows weak \ion{Si}{2} lines and spectral evolution similar to other high-luminosity Type Iax SNe, but also a prominent early-time \ion{C}{2} line, like lower-luminosity Type Iax SNe. The late-time optical spectrum of SN~2024pxl closely matches that of SN~2014dt, and its NIR spectral evolution aligns with that of other well-studied, high-luminosity Type Iax SNe. The spectral-line expansion velocities of SN~2024pxl are at the lower end of the Type Iax SN velocity distribution, and the velocity distribution of iron-group elements compared to intermediate-mass elements suggests that the ejecta are mixed on large scales, as expected in pure deflagration models. SN~2024pxl exhibits characteristics intermediate between those of high-luminosity and low-luminosity Type~Iax SNe, further establishing a link across this diverse class.

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arXiv2026

SN 2023zcu: A Type IIP SN with Early Flash Features

We present a detailed photometric and spectroscopic analysis of the Type IIP supernova SN~2023zcu, which exploded in the galaxy NGC~2139 (redshift $z$ = 0.006). SN~2023zcu exhibits a well-sampled light curve covering the rise, plateau, and nebular phases. It has an optically thick phase of $100.6 \pm 0.6$ d with a magnitude drop of $\sim$1.7 mag in the {\em V} band during the transition between the plateau and the nebular phases. Weak emission features in the early-time spectra indicate a low-level interaction between circumstellar material (CSM) and the SN ejecta. The spectral evolution is well sampled and exhibits a prominent P-Cygni profile of H$α$, a defining characteristic of Type IIP SNe. Signatures of metal-line formation (e.g., \ion{Fe}{2}, \ion{Ca}{2} near-infrared triplet) are also evident in the spectra as the SN evolves. Spectral modeling with the radiative-transfer code \texttt{TARDIS} during the early photospheric phase (8.7--35.5 d since explosion) yields photospheric temperatures decreasing from $\sim$9,000 to $\sim$6,000 K and expansion velocities declining from $\sim$10,000 to $\sim$5,400 km s$^{-1}$. A tailored expanding photosphere method (EPM) fit based on the \texttt{TARDIS} models provides a distance estimate of $27.8 \pm 2.0$ Mpc. Nebular-phase spectra and bolometric light-curve modeling suggest a progenitor mass in the range 12--15 M$_\odot$. This thorough analysis helps to constrain progenitor properties and explosion parameters, thereby strengthening our understanding of Type IIP SNe.

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arXiv2026

A Study of Two Type IIb Supernovae: SNe 2008aq and 2019gaf

We present photometric and spectroscopic studies of two core-collapse supernovae (SNe) 2008aq and 2019gaf in the optical wavelengths. Light curve and spectral sequence of both the SNe are similar to those of other Type IIb SNe. The pre-maximum spectrum of SN~2008aq showed prominent H $α$ lines, the He lines started appearing in the near maximum spectrum. The near maximum spectrum of SN~2019gaf shows shallow H$α$ absorption and He lines with almost similar strength. Both the SNe show transition from hydrogen-dominated spectra to helium-dominated spectra within a month after maximum brightness. The velocity evolution of SN~2008aq matches well with those of other well-studied Type IIb SNe, while SN~2019gaf shows higher velocities. Close to maximum light, the H $α$ and He I line velocities of SN~2019gaf are $\sim$ 2000 km sec$^{-1}$ and $\sim$ 4000 km sec$^{-1}$ higher than other well-studied Type IIb SNe. Semi-analytical modeling indicates SN~2019gaf to be a more energetic explosion with a smaller ejecta mass than SN~2008aq. The zero-age main-sequence (ZAMS) mass of the progenitor estimated using the nebular spectra of SN~2008aq ranges between 13 to 20 M$_\odot$, while for SN~2019gaf, the inferred ZAMS mass is between 13 to 25 M$_\odot$. The [O I] to [Ca II] lines flux ratio favors a less massive progenitor star in a binary system for both the SNe.

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arXiv2025

SN 2024aecx: a fast-evolving Type IIb supernova with a prominent shock-cooling peak

SN 2024aecx is a nearby ($\sim$11 Mpc) Type IIb SN discovered within $\sim$1 d after explosion. In this paper we report high-cadence photometric (typically 0.5$\sim$1 day) and spectroscopic follow-up observations, conducted from as early as 0.27 d post discovery out to the nebular phase at 158.4 d. We analyze the environment of SN 2024aecx and derive a new distance (11.3$\pm$1.1 Mpc), metallicity and host extinction. The light curve exhibits a hot and luminous shock-cooling peak at the first few days, followed by a main peak with very rapid post-maximum decline. The earliest spectra are blue and featureless, while from 2.3 d after discovery prominent P-Cygni profiles emerge. At nebular phase, the emission lines exhibit asymmetric and double-peaked profiles, indicating asphericity and/or early dust formation in the ejecta. Nebular spectral modelling indicates a blueshifted O-rich clump moving toward observer, and the $[\text{OI}]/[\text{CaII}]$ line ratio suggests an intermediate-mass progenitor. We simulated the progenitor and explosion using a two-component model of shock cooling and radioactive $^{56}$Ni heating; our model favors an extended, low-mass H-rich envelope with $M_{\mathrm{e}} = 0.04\pm{0.01} M_{\odot}$ and a low ejecta mass of$M_{\mathrm{ej}} = 1.55^{+0.18}_{-0.14} M_{\odot}$. And the nebular-phase spectra and light-curve modelling both suggest that it most likely originated from an intermediate-mass binary progenitor system. The comprehensive monitoring of SN 2024aecx, coupled with the detailed characterization of its local environment, establishes it as a benchmark event for probing the progenitors and explosion mechanisms of Type IIb SNe.

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arXiv2025

What do gravitational-wave observations tell us about Luminous Red Novae?

Luminous Red Novae (LRNe) have been argued to be related to the ejection of common envelopes (CEs) in binary star systems. Ejection of CEs leads to tightened stellar orbits capable of forming compact binaries that merge in Hubble time. As these mergers are seen by gravitational-wave (GW) detectors such as LIGO, Virgo and KAGRA (LVK), we ask what the merger rates of compact binaries in LVK tell us about the fraction of LRNe that lead to the formation of compact binaries that merge in Hubble time. Using the observed volumetric rates of LRNe from the Zwicky Transient Facility (ZTF) and of compact binary mergers from LVK observations, we derive limits on the fraction of LRNe that produce compact binaries that merge in Hubble time. Assuming the LRNe rate closely follows the star formation rate at any redshift, we use the delay time distribution models for compact binaries to compute the compact binary merger rate. A comparison of this merger rate with the latest volumetric rates of compact binary mergers from the fourth GW transient catalog (GWTC-4) at the present epoch of LVK allows us to constrain the above fraction. We find that only a fraction as small as $\sim 10^{-3}$ (median) of the LRNe correspond to the GW-observed binary neutron star (BNS) and neutron star-black hole (NSBH) mergers. This potentially implies that the majority of the LRNe population will not lead to mergers of compact objects, but other end products, such as stellar mergers.

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arXiv2025

JWST and Ground-based Observations of the Type Iax Supernovae SN 2024pxl and SN 2024vjm: Evidence for Weak Deflagration Explosions

We present panchromatic optical $+$ near-infrared (NIR) $+$ mid-infrared (MIR) observations of the intermediate-luminosity Type Iax supernova (SN Iax) 2024pxl and the extremely low-luminosity SN Iax 2024vjm. JWST observations provide unprecedented MIR spectroscopy of SN Iax, spanning from $+$11 to $+$42 days past maximum light. We detect forbidden emission lines in the MIR at these early times while the optical and NIR are dominated by permitted lines with an absorption component. Panchromatic spectra at early times can thus simultaneously show nebular and photospheric lines, probing both inner and outer layers of the ejecta. We identify spectral lines not seen before in SN Iax, including [Mg II] 4.76 $μ$m, [Mg II] 9.71 $μ$m, [Ne II] 12.81 $μ$m, and isolated O I 2.76 $μ$m that traces unburned material. Forbidden emission lines of all species are centrally peaked with similar kinematic distributions, indicating that the ejecta are well mixed in both SN 2024pxl and SN 2024vjm, a hallmark of pure deflagration explosion models. Radiative transfer modeling of SN 2024pxl shows good agreement with a weak deflagration of a near-Chandrasekhar-mass white dwarf, but additional IR flux is needed to match the observations, potentially attributable to a surviving remnant. Similarly, we find SN 2024vjm is also best explained by a weak deflagration model, despite the large difference in luminosity between the two supernovae. Future modeling should push to even weaker explosions and include the contribution of a bound remnant. Our observations demonstrate the diagnostic power of panchromatic spectroscopy for unveiling explosion physics in thermonuclear supernovae.

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arXiv2025

SN 2023xgo: Helium-rich Type Icn or Carbon-Flash Type Ibn supernova?

We present observations of SN~2023xgo, a transitional Type Ibn/Icn supernova, from $-5.6$ to $+63$~days relative to the $r$-band peak. Early spectra show C~III $λ5696$ emission reminiscent of Type~Icn SNe, which later gives way to Type~Ibn features. The He~I velocities ($1800$--$10{,}000$~km~s$^{-1}$) and pseudo-equivalent widths are among the highest in the Ibn/Icn class. The light curve declines at $0.14$~mag~d$^{-1}$ until $+30$~days, consistent with SNe~Ibn/Icn and slower than fast transients. SN~2023xgo is the faintest in our SN~Ibn sample ($M_r=-17.65\pm0.04$) but shows typical color and host properties. Semi-analytical modeling of the light curve suggests a compact CSM shell ($\sim 10^{12}$--$10^{13}$~cm) and a mass-loss rate of $10^{-4}$--$10^{-3}$~$M_{\odot}$~yr$^{-1}$, with CSM and ejecta masses of $\sim 0.22$ and $0.12$~$M_{\odot}$, respectively. Post-maximum light-curve and spectral modeling favor a $\sim 3$~$M_{\odot}$ helium-star progenitor with extended ($\sim 10^{15}$~cm), stratified CSM (density exponent $n=2.9$) and a mass-loss rate of $0.1$--$2.7$~$M_{\odot}$~yr$^{-1}$. These two mass-loss regimes imply a radially varying CSM, shaped by asymmetry or temporal changes in the progenitor's mass loss. This behavior is compatible with both binary and single-star evolution. We argue that the early Icn-like features arise from hot carbon ionization and fade to Ibn-like signatures as the ejecta and CSM cool, making SN~2023xgo a rare probe of the connection between SNe~Icn, SNe~Ibn, and Ibn events with ejecta signatures.

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arXiv2025

SN 2023vbg: A Type IIn Supernova Resembling SN 2009ip, with a Long-Duration Precursor and Early-Time Bump

Type IIn supernovae (SNe) resembling SN 2009ip (09ip-like SNe) originate from the interaction between circumstellar material (CSM) and the ejecta. This subclass not only shares similar observational properties around the maximum, but is commonly characterized by a long-duration precursor before its maximum. Investigating the observed properties of the precursor provides constraints on the mass-loss history of the progenitor. We present observational data of SN 2023vbg, a 09ip-like type IIn SN that displayed unique observational properties compared to other 09ip-like SNe. SN 2023vbg showed a long-duration precursor at approximately Mg = -14 mag lasting for about 100 days, followed by a bright bump at Mg = -17 mag at 12-25 days before the maximum. The luminosity of the precursor is similar to those of other 09ip-like SNe, but the bright bump has not been observed in other cases. After reaching the peak luminosity, the light curve exhibited a relatively smooth decline. While the H-alpha profile displays two velocity components (approximately 500 and 3000 km/s), a broad component observed in other 09ip-like SNe was not seen, though it may emerge later. We suggest that these properties are explained by the difference in the CSM structure as compared to other 09ip-like SNe; SN 2023vbg had an inner denser CSM component, as well as generally smooth CSM density distribution on a more extended scale, than in the others. Such diversity of CSM likely reflects the diversity of pre-SN outbursts, which in turn may mirror the range of evolutionary pathways in the final stages of the progenitors.

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