PSM2023 Participants

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 endeavor. We have developed and executed an extensive program with the wide field of view of the Zwicky Transient Facility (ZTF) camera, mounted on the Palomar 48 inch Oschin telescope (P48), to perform target-of-opportunity (ToO) observations on 15 Fermi-GBM SGRBs during 2018 and 2020-2023. Bridging the large sky areas with small field of view optical telescopes in order to track the evolution of potential candidates, we look for the elusive SGRB afterglows and kilonovae (KNe) associated with these high-energy events. On August 2020, a ZTF-discovered short GRB afterglow showed ambiguous characteristics and late-time photometry unveiled a supernova, making GRB 200826A the shortest duration GRB from a collapsar. Here we discuss the impact of our ToO searches and the prospects of optical GRB science from Palomar observatory.

Accreting compact binaries vary on every observable timescale. Variations by orders of magnitude are observed on timescales from weeks to decades - in many cases these are explained as disk instabilities. Orbital variations on timescales of hours to days constrain the binary parameters of the systems. Recently, there has been increasing interest in short timescale variability (seconds to minutes) in high energy and optical/IR wavelengths, which may reveal activity near the surface or event horizons of the accreting objects. The Hale telescope with imaging instruments is ideal for this work, as high S/N must be obtained in short exposures. Here we report both on the general state of this work, and on the specific source Swift J1858.6-0814, the optical counterpart of which was discovered at Palomar.

I will review some of the key early 1 to 20 micron observations with the 200 inch telescope from 1966 to 1977. The observations were made primarily with Gerry Neugebauer, but also included work with G. Munch and Jim Westphal. Topics to discussed include: Discovery of stars in the central pc of the Milky Way, Discovery of the BN object in the Orion Nebula and Measurement of the Crab Nebula Pulsar at 2.2 microns.

NASA's first technology demonstration of optical communications from planetary distances (upto 2 AU) is being implemented by the Deep Space Optical Communication (DSOC) Project at JPL. The Psyche spacecraft hosting the DSOC Flight Laser Transceiver (FLT) is preparing for launch in October 2023. The downlink laser signal from the FLT will be received at the Palomar Observatory, 200-inch telescope. A photon counting receiver located in the coude spectrograph room will be used to detect the laser signal and perform real time signal processing to extract information code words transmitted from space. Operations readiness tests completed so far will be summarized and the operations strategy for supporting the technology demonstration, starting in November 2023, will be discussed.

It's well known that RW Porter played a leading role in developing the distinctive architecture of Palomar Observatory. What is less well-known is how Porter came to the Art Deco/Streamline Modern forms he used in the design of observatory domes and buildings. In this contribution we will trace the architectural "genealogy" of the observatory back to neoclassical concepts and the height of the NY/LA Art Deco period in the late 1920s/early 1930s.

Palomar is no stranger to exciting Solar System discoveries. Palomar has made headlines and expanded our knowledge of the Solar System such as the discovery of a Jupiter-impacting comet, distant large bodies, and two of five near-Earth asteroid classes in addition to the famous green comet, C/2022 E3 (ZTF), visible to millions of people around the globe. I will describe work leading to some of these discoveries and prospects for the future.

PARVI is a near infrared (J, H-band) echelle spectrograph on the Palomar 5 meter telescope. Motivated by ongoing challenges with other seeing-limited spectrographs, PARVI is fed by a diffraction limited beam via single mode fibers courtesy of the P3K adaptive optics system. Here I present a status report on our efforts commissioning PARVI. I provide an overview of the instrument, description of our data processing algorithms, and scientific capabilities with PARVI. I also highlight an unforeseen source of error induced by birefringent sensitive optics and our choices to mitigate them. I conclude with preliminary on-sky results demonstrating the early performance of PARVI.

Eruptive mass loss of massive stars prior to supernova (SN) explosion is key to understanding their evolution and end fate. An observational signature of pre-SN mass loss is the detection of an early, short-lived peak prior to the radioactive-powered peak in the lightcurve of the SN. Such an early peak is common for double-peaked Type IIb SNe with an extended Hydrogen envelope but is uncommon for normal Type Ibc SNe with very compact progenitors. We systematically study a sample of 14 double-peaked Type Ibc SNe out of 475 Type Ibc SNe detected by the Zwicky Transient Facility. The rate of these events is $sim 3-9 %$ of Type Ibc(BL) SNe and $sim 1-2 %$ of core-collapse SNe. We perform a holistic analysis of this sample's photometric and spectroscopic properties. This sample suggests that SNe with progenitor mass $lesssim$ 12 Msun undergo late-time mass transfer of binary He-stars with core mass of $lesssim 3$ Msun. Meanwhile, the SNe with higher progenitor masses are consistent with wave-driven mass loss or pulsation-pair instability-driven mass loss simulations.

Understanding low-frequency radio emission from stars and how it might be related to space-weather has been hindered by a lack of simultaneous observations at other parts of the electromagnetic spectrum. To remedy this, we have developed Flarescope, a small, high-precision, fully-automated optical telescope dedicated to monitoring nearby, young, Sun-like stars. This observatory will observe targets simultaneously with the recently upgraded Long Wavelength Array at the Owens Valley Radio Observatory. Here, we present the design and status of Flarescope.

The effective telescope aperture ahead of an astronomical faint-object spectrograph is a function of the image quality delivered to the spectrograph entrance slit/slicer. We present details on SIGHT, a new, integrated adaptive optics (AO) facility for the 200" (5 meter) telescope that uses a pilot-safe UV laser guide star and MEMS deformable mirror to partially compensate the turbulence of Earth's atmosphere across all wavelengths. SIGHT is design to work at most pointings and under nearly all seeing conditions, providing 30-50% reduction in image FWHM, reducing sky noise and allowing increased spectral resolution. Based on wave-optics AO simulations, SIGHT is expected to increase the effective aperture of the Hale Telescope for background-limited science to roughly 250" (6.3 meters.)

Cryoscope is a quarter-scale prototype for a fully cryogenic, wide-field (50 sq. deg. FoV) near-infrared telescope at Dome C in Antarctica. Powered by a novel optomechanical design, Cryoscope will perform diffraction-limited imaging in the photometric K-band, becoming the widest and deepest field NIR imager of its kind. The full-scale telescope will achieve the same volumetric survey speed in K-band as LSST does in y-band. On-sky tests will begin this summer at Palomar. Upon deploying to Antarctica, Cryoscope will advance galactic time domain astronomy and exoplanet science while setting the stage for the meter class telescope that will be a discovery engine for multi-messenger events.

The Next Generation Palomar Spectrograph (NGPS) will replace the Double Spectrograph (DBSP) as the workhorse optical spectrograph on the Palomar 200-inch telescope. NGPS is being jointly developed by Caltech and NAOC/NIAOT. Here we present an update on the status of NGPS and outline the prospective performance of the instrument. Tools currently in development for observation planning and data reduction will also be presented.

The Transiting Exoplanet Survey Satellite (TESS) has discovered over 250 transiting planets, with more than 6000 candidates yet to be validated. Previous studies have used TESS photometry and statistical tools to quantify the false positive probability (FPP) of TESS candidates. Common types of false positive signals (e.g., eclipsing binary stars) can be ruled out using multi-wavelength transit observations, since the light curves of transiting planets should be nearly achromatic. However, popular statistical tools such as TRICERATOPS currently lack the functionality to incorporate multi-wavelength light curves from ground-based observatories into the calculation of the FPP. These light curves can be significantly more precise than the TESS photometry, and are especially helpful for confirming TESS candidates with low signal-to-noise ratios. In this work, we observed several TESS candidates with Palomar Observatory and modified TRICERATOPS to incorporate these infrared observations. In doing so, we quantify the impact of multi-wavelength observations on the FPPs for these TESS candidates.

The accretion disks of supermassive black holes offer a significant channel for heavy stellar mass binary black hole mergers detectable with LIGO and with a guaranteed electromagnetic counterpart. In this talk, we will review how the Palomar facilities are key to studying these highly dynamic environments and the suite of events in them and what they are revealing about the structure of active galactic nuclei and the expansion rate of the universe.

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Models predict that planets with water-rich compositions may be common around low-mass stars, but definitive evidence for the existence of water worlds has remained elusive. Precise mass and radius measurements for small planets allow us to identify candidate water worlds which have bulk densities too low to be consistent with a rocky composition, and masses too low to retain any H-rich envelope against hydrodynamic escape. Dynamical interactions between adjacent planets in near-resonant multi-planet systems produce transit timing variations (TTVs) that can be observed with high-precision photometry, and measurements of these TTVs can be inverted to produce constraints on planetary densities. For the past two years, the 200" Hale Telescope has collected dozens of transit observations for small, Earth-sized exoplanets in nearby multi-planet M dwarf systems. I will discuss some of the promising early results from this survey of candidate water worlds.

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Luminous Red Novae (LRNe) are a unique class of transients resulting from a stellar merger or common envelope (CE) ejection in massive binaries. As such, they offer valuable insights into the poorly understood CE evolution. In this talk, I will discuss results from a systematic search for LRNe using the Zwicky Transient Facility. I will also describe the newly commissioned WINTER infrared time-domain surveyor at Palomar, and how an ongoing WINTER search for LRNe will enhance our understanding of them.

Close-in exoplanets are strongly shaped by their stellar environments. The high energy irradiation received by these planets can strip away their hydrogen-rich gas envelopes, while planets formed around low-mass stars may be able to accrete significant quantities of water. In my talk I will provide an overview of two ongoing programs that utilize Palomar/WIRC to measure the atmospheric mass loss rates of gas giant exoplanets and identify new candidate water worlds orbiting nearby M dwarfs.

We present three classical novae (AT2019qwf, AT2021quw, and AT2022sfe) that erupted within the field of the Transiting Exoplanet Survey Satellite (TESS) and were observed by various instruments. We analyze the mechanism of the eruption with luminosity flares before, during, and after optical maximum, and compare the changes in spectra with respect to time evolution and how these luminosity flares signal change in the eruption, e.g. collisions of mass ejections at different velocities at different points in the process.

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The time evolution and possible mass loss from primordial atmospheres is critical towards understanding the exoplanet occurrence statistics. Previous work has used transit photometry with an ultranarrowband filter centered on the 10830Å metastable He line to constrain outflows from giant planets. We will discuss some current efforts to characterize mass loss in different regions of parameter space: small and young exoplanets. Specifically, we will report on ongoing data collection and share plans for upcoming research.

The variability of the accretion flow of black holes can be used to probe the accretion flow’s properties. We report on the short-term variability of the non-stellar emission from the quiescent X-ray binary A0620-00. There appears to be quasi-periodic variability on timescales of 30-40 minutes at orbital phases 0.4 < θ < 0.7, but not θ < 0.4. Understanding this dependence on phase will yield insights into quiescent black holes and their accretion flow model.

Palomar has a rich tradition of sky surveys, and follow-up observing. This has led to a very large number of discoveries, and indeed to programs. We will provide an overview of the surveys and highlight the beginnings of some science that ensued.

The Satellites Around Galactic Analogs (SAGA) Survey identifies satellite galaxies around nearby Milky Way analogs. Combining the power of multifiber and single-slit (including Palomar DBSP) spectroscopy, we have obtained more than 50,000 galaxy redshifts, significantly increasing spectroscopic coverage for very low redshift dwarf galaxies (17 &lt; r &lt; 20.75). Our upcoming Data Release III will include a satellite census of 100 Milky Way-mass systems, providing a unique data set that places the Local Group in a cosmological context.

The census of the coldest constituents of the Solar Neighborhood, here defined as a 20pc-radius sphere around the Sun, remains incomplete. Completing such census is one of the driving goals for the CatWISE and "Backyard Worlds: Planet Nine" teams, who have discovered hundreds of new late-T and Y dwarfs using data from WISE/NEOWISE. The Hale Telescope and WIRC have played a major role in the characterization of these new discoveries. Here I present the results of our on-going observing campaign, which is revealing a stunning diversity among the substellar population, a diversity that atmospheric models suggest is driven by metallicity.

A key to understanding the weather of Jovian exoplanet atmospheres lies in characterizing microphysical processes that drive condensate cloud formation.  In this poster, we discuss how spectro-polarimetric observations of Brown Dwarfs (BDs) can be used to better understand cloud formation and distribution in both BD and giant exoplanet atmospheres, and report the first results of a spectro-polarimetric survey of L/T transition BDs using WIRC+Pol at the 200-inch Hale telescope.

Since early 1994, my career has been vastly impacted and enabled by Palomar, including the JHU Adaptive Optics Coronagraph on the 60-inch, several of Keith Matthews's pioneering instruments, Palm-AO, P3K, PHARO, PTI, Project 1640 and now PARVI, among other projects. Palomar is the world's premier site for adventures in astrophysics innovations, critical to all sorts of advances over the years and into the future.

The ultimate origins of the extragalactic fast radio bursts (FRBs) remain elusive. However, significant insights are being gained from detailed studies of FRB host galaxies and environments. Stellar population synthesis models of FRB hosts, and nebular-emission studies at host locations, are being used to constrain the progenitor formation channels. The Deep Synoptic Array (DSA-110) at the Owens Valley Radio Observatory is now the leading machine for the simultaneous discovery and arcsecond-localization of FRBs, delivering an unprecedented event per week. I will present results on FRB progenitors, and on the extragalactic baryon contents along FRB sightlines, from observations at the Palomar and Keck observatories.

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White dwarfs are the most abundant stellar remnant and serve as excellent high energy astrophysical laboratories, particularly when in close binary systems. Cataclysmic variables (CVs) are systems in which a white dwarf accretes from a Roche lobe filling donor star, typically via an accretion disk which can outshine the rest of the system. Polars make up nearly a third of all CVs, and are systems in which the magnetic field of the white dwarf is so strong (up to a few hundred MG) that matter is channeled along the field lines instead of forming a disk. I will explain how I have used three of Palomar's telescopes: the 48-inch, 60-inch, and 200-inch to discover dozens of new polars and add to our understanding of their formation and evolution.

Most stars in the Universe today that have died have become white dwarfs. These simple objects, especially when accreting from a close companion, have shown remarkable diversity through surveys across the electromagnetic spectrum. Polars are systems where a white dwarf with a > 10 MG magnetic field accretes from a donor star. In this poster, I show how the Palomar 48-inch, 60-inch, and 200-inch telescopes have played a crucial role in the discovery and characterization of polars. These systems are everywhere, and ongoing studies are showing the crucial role they play in the final stages of binary star evolution.

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Gamma-ray bursts (GRBs) are intense flashes of radiation with panchromatic counterparts, powered by massive stellar collapse or mergers of neutron stars. I highlight advances in GRBs made by then-early career researchers (now our eminent senior colleagues) at Palomar. I discuss the synergy between ground-based optical astronomy, NASA's astrophysics fleet, and open data services like GCN and HEASARC. I conclude with Palomar’s vital role and the renewed importance of GRBs in this era of multimessenger astronomy.

We present a detailed analysis of SN 2020qmp, a nearby type IIP core-collapse supernova (CCSN) discovered by the Palomar Gattini-IR survey. Through determining or constraining the main properties of SN 2020qmp and of its progenitor, we illustrate how the study of this event helps our general understanding of stellar progenitors and circumstellar medium interactions in CCSNe. We also show that forthcoming near-infrared surveys will enable us to do a nearly complete census of CCSNe in the local universe.

The ZTF neutrino follow-up program is a census of neutrino-coincident transients with the P48, which led to the identification of 2 Tidal Disruption Events (TDEs) as probable neutrino sources. These are only the second and third sources of the presently-unexplained diffuse neutrino flux discovered by the IceCube. Both transients required multi-wavelength follow-up to fully characterise, including dedicated observations with the P200. This highlights the unique power of the Palomar Observatory ecosystem for advancing multi-messenger astrophysics.

White dwarfs with transiting planetary debris offer a window into the late stages of planetary system evolution, as planetary bodies that survived the post-main sequence stages of the host star are scattered onto star grazing orbits and tidally disrupted. We are using a multi-instrument approach involving ZTF, DBSP, CHIMERA, and WIRC to both discover and more fully characterize these systems, to better understand the nature of the objects being accreted by white dwarf stars.

For about a decade starting in 1972 a determined and eclectic group of astronomers used the 200-inmch during twilight hours for observations at 1mm, and, very rarely, at 350um. This poster will review the scientific, technological, and community-building features of this program, which exemplifies the benefits of the 200-inch to Caltech, JPL, and beyond.