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The October 2022 flare in OJ 287 and the mass of its primary black hole
Mauri J. Valtonen, Staszek Zola, Manpreet Singh +21
The bright blazar OJ~287 has demonstrated a sequence of flares, which are well explained by a quasi-Keplerian orbit model. The flares are associated with the impact of the secondar…
Identifying the secondary jet in the RadioAstron image of OJ~287
Mauri J. Valtonen, Lankeswar Dey, Staszek Zola +26
The 136 year long optical light curve of OJ~287 is explained by a binary black hole model where the secondary is in a 12 year orbit around the primary. Impacts of the secondary on…
An Extreme Scattering Event Toward PSR J2313+4253
Zachary C. Zelensky, Jacob E. Turner, Juan G. Lebron Medina +7
We present evidence of an extreme scattering event (ESE) toward PSR J2313+4253 using high-cadence observations taken with the Green Bank Observatory 20m telescope. The high density…
A Statistical Analysis of Crab Pulsar Giant Pulse Rates
Graham M. Doskoch, Andrea Basuroski, Kriisa Halley +18
A small number of pulsars are known to emit giant pulses, single pulses much brighter than average. Among these is PSR J0534+2200, also known as the Crab pulsar, a young pulsar wit…
Evidence of jet activity from the secondary black hole in the OJ287 binary system
Mauri J. Valtonen, Staszek Zola, Alok C. Gupta +29
We report the study of a huge optical intraday flare on November 12, 2021, at 2 am UT, in the blazar OJ287. In the binary black hole model it is associated with an impact of the se…
The Pulsar Science Collaboratory: Multi-Epoch Scintillation Studies of Pulsars
Jacob E. Turner, Juan G. Lebron Medina, Zachary Zelensky +13
We report on findings from scintillation analyses using high-cadence observations of eight canonical pulsars with observing baselines ranging from one to three years. We obtain sci…
Searching for precursor activity of Type IIn Supernovae
A. Reguitti, G. Pignata, A. Pastorello +4
We conducted a search for luminous outbursts prior to the explosion of Type IIn Supernovae (SNe IIn). We built a sample of 27 objects spectroscopically classified as SNe IIn, all l…
Strong Carbon Features and a Red Early Color in the Underluminous Type Ia SN 2022xkq
Jeniveve Pearson, David J. Sand, Peter Lundqvist +85
We present optical, infrared, ultraviolet, and radio observations of SN 2022xkq, an underluminous fast-declining type Ia supernova (SN Ia) in NGC 1784 ( Mpc),…
Characterizing the Rapid Hydrogen Disappearance in SN2022crv: Evidence of a Continuum between Type Ib and IIb Supernova Properties
Yize Dong, Stefano Valenti, Chris Ashall +52
We present optical and near-infrared observations of SN~2022crv, a stripped envelope supernova in NGC~3054, discovered within 12 hrs of explosion by the Distance Less Than 40 Mpc S…
Profound optical flares from the relativistic jets of active galactic nuclei
Gopal Bhatta, Staszek Zola, M. Drozdz +11
Intense outbursts in blazars are among the most extreme phenomena seen in extragalactic objects. Studying these events can offer important information about the energetic physical…
On the need of an ultramassive black hole in OJ 287
Mauri J. Valtonen, Staszek Zola, Achamveedu Gopakumar +25
The highly variable blazar OJ~287 is commonly discussed as an example of a binary black hole system. The 130 year long optical light curve is well explained by a model where the ce…
Observational Implications of OJ 287's Predicted 2022 Disk Impact in the Black Hole Binary Model
Mauri J. Valtonen, Lankeswar Dey, Achamveedu Gopakumar +24
We present a summary of the results of the OJ 287 observational campaign, which was carried out during the 2021/2022 observational season. This season is special in the binary mode…
A comprehensive optical search for pre-explosion outbursts from the quiescent progenitor of SN~2023ixf
Yize Dong, David J. Sand, Stefano Valenti +13
We perform a comprehensive search for optical precursor emission at the position of SN~2023ixf using data from the DLT40, ZTF and ATLAS surveys. By comparing the current data set w…
Early Spectroscopy and Dense Circumstellar Medium Interaction in SN 2023ixf
K. Azalee Bostroem, Jeniveve Pearson, Manisha Shrestha +53
We present the optical spectroscopic evolution of SN~2023ixf seen in sub-night cadence spectra from 1.18 to 14 days after explosion. We identify high-ionization emission features,…
Shock Cooling and Possible Precursor Emission in the Early Light Curve of the Type II SN 2023ixf
Griffin Hosseinzadeh, Joseph Farah, Manisha Shrestha +28
We present the densely sampled early light curve of the Type II supernova (SN) 2023ixf, first observed within hours of explosion in the nearby Pinwheel Galaxy (Messier 101; 6.7 Mpc…
The Early Light Curve of SN 2023bee: Constraining Type Ia Supernova Progenitors the Apian Way
Griffin Hosseinzadeh, David J. Sand, Sumit K. Sarbadhicary +39
We present very early photometric and spectroscopic observations of the Type Ia supernova (SN Ia) 2023bee, starting about 8 hr after the explosion, which reveal a strong excess in…
SN 2022acko: the First Early Far-Ultraviolet Spectra of a Type IIP Supernova
K. Azalee Bostroem, Luc Dessart, D. John Hillier +41
We present five far- and near-ultraviolet spectra of the Type II plateau supernova, SN 2022acko, obtained 5, 6, 7, 19, and 21 days after explosion, all observed with the Hubble Spa…
Refining the 2022 OJ 287 impact flare arrival epoch
Mauri J. Valtonen, Staszek Zola, Gopakumar +24
The bright blazar OJ~287 routinely parades high brightness bremsstrahlung flares, which are explained as being a result of a secondary supermassive black hole (SMBH) impacting the…
Catching profound optical flares in blazars
Gopal Bhatta, Staszek Zola, M. Drozdz +11
Flaring episodes in blazars represent one of the most violent processes observed in extra-galactic objects. Studies of such events shed light on the energetics of the physical proc…
Refining the prediction for OJ 287 next impact flare arrival epoch
Mauri J. Valtonen, Staszek Zola, A. Gopakumar +23
The bright blazar OJ~287 routinely parades high brightness bremsstrahlung flares which are explained as being a result of a secondary supermassive black hole (SMBH) impacting the a…
Circumstellar Medium Interaction in SN 2018lab, A Low-Luminosity II-P Supernova observed with TESS
Jeniveve Pearson, Griffin Hosseinzadeh, David J. Sand +21
We present photometric and spectroscopic data of SN 2018lab, a low luminosity type IIP supernova (LLSN) with a V-band peak luminosity of mag. SN 2018lab was discovere…
Early Lightcurves of Type Ia Supernovae are Consistent with Nondegenerate Progenitor Companions
J. Burke, D. A. Howell, D. J. Sand +16
If Type Ia supernovae (SNe~Ia) result from a white dwarf being ignited by Roche lobe overflow from a nondegenerate companion, then as the supernova explosion runs into the companio…
Constraining the Progenitor System of the Type Ia Supernova 2021aefx
Griffin Hosseinzadeh, David J. Sand, Peter Lundqvist +25
We present high-cadence optical and ultraviolet light curves of the normal Type Ia supernova (SN) 2021aefx, which shows an early bump during the first two days of observation. This…
Weak Mass Loss from the Red Supergiant Progenitor of the Type II SN 2021yja
Griffin Hosseinzadeh, Charles D. Kilpatrick, Yize Dong +56
We present high-cadence optical, ultraviolet (UV), and near-infrared data of the nearby ( Mpc) Type II supernova (SN) 2021yja. Many Type II SNe show signs of interactio…