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ASASSN-14ko is a nuclear transient at the center of the AGN ESO 253-G003 that undergoes periodic flares. Optical flares were first observed in 2014 by the All-Sky Automated Survey for Supernovae (ASAS-SN) and their peak times are well-modeled with a period of $115.2^{+1.3}_{-1.2}$ days and period derivative of $-0.0026 \pm 0.0006$. Here we present ASAS-SN, Chandra, HST/STIS, NICER, Swift, and TESS data for the flares that occurred in December 2020, April 2021, July 2021, and November 2021. The HST/STIS UV spectra evolve from blue shifted broad absorption features to red shifted broad emission features over $\sim$10 days. The Swift UV/optical light curves peaked as predicted by the timing model, but the peak UV luminosities varied between flares and the UV flux in July 2021 was roughly half the brightness of all other peaks. The X-ray luminosities consistently decreased and the spectra became harder during the UV/optical rise but apparently without changes in absorption. Finally, two high-cadence TESS light curves from December 2020 and November 2018 showed that the slopes during the rising and declining phases changed over time, which indicates some stochasticity in the flare's driving mechanism. ASASSN-14ko remains observationally consistent with a repeating partial tidal disruption event, but, these rich multi-wavelength data are in need of a detailed theoretical model., Comment: 25 pages, 14 figures, 4 tables; Submitted to ApJ, comments welcome

We analyze high-cadence data from the Transiting Exoplanet Survey Satellite (TESS) of the ambiguous nuclear transient (ANT) ASASSN-18el. The optical changing-look phenomenon in ASASSN-18el has been argued to be due to either a drastic change in the accretion rate of the existing active galactic nucleus (AGN) or the result of a tidal disruption event (TDE). Throughout the TESS observations, short-timescale stochastic variability is seen, consistent with an AGN. We are able to fit the TESS light curve with a damped-random-walk (DRW) model and recover a rest-frame variability amplitude of $\hat{\sigma} = 0.93 \pm 0.02$ mJy and a rest-frame timescale of $\tau_{DRW} = 20^{+15}_{-6}$ days. We find that the estimated $\tau_{DRW}$ for ASASSN-18el is broadly consistent with an apparent relationship between the DRW timescale and central supermassive black hole mass. The large-amplitude stochastic variability of ASASSN-18el, particularly during late stages of the flare, suggests that the origin of this ANT is likely due to extreme AGN activity rather than a TDE., Comment: 13 pages, 8 figures. Will be submitted to AAS journals. Comments welcome

We present the results of a systematic search for AGN in TESS light curves of dwarf galaxies. Evidence of short-term flux changes in dwarf galaxies can reveal an AGN even when emission line ratios fail to do so. Studies of dwarf AGN are essential for a general understanding of the relationship between black hole and galaxy evolution. The timescale from the commonly-used damped random walk model has been shown to correlate with black hole mass, but further studies are required to understand the physical processes driving this empirical model’s effectiveness. Partially because of this timescale relation, TESS is a unique tool for the identification of dwarf AGN; a light curve from a single sector can reveal adequate variability. We demonstrate a successful methodology that accounts for TESS systematics and contamination by variable stars. The newly-identified AGN help populate scaling relations at the low-mass end and demonstrate the crucial role of TESS in studies of dwarf AGN and AGN in general., {"references":["Baldassare et al. (2020). A Search for Optical AGN Variability in 35,000 Low-mass Galaxies with the Palomar Transient Factory","Burke et al. (2020). Optical Variability of the Dwarf AGN NGC 4395 from the Transiting Exoplanet Survey Satellite","Fausnaugh et al. (2021). Early-time Light Curves of Type Ia Supernovae Observed with TESS","Tonry et al. (2018). The ATLAS All-Sky Stellar Reference Catalog","Heinze et al. (2018). A First Catalog of Variable Stars Measured by the Asteroid Terrestrial-impact Last Alert System (ATLAS)","Jayasinghe et al. (2021). The ASAS-SN catalogue of variable stars IX: The spectroscopic properties of Galactic variable stars","Baldwin et al. (1981). Classification parameters for the emission-line spectra of extragalactic objects.","Fernandes et al. (2011). A comprehensive classification of galaxies in the Sloan Digital Sky Survey: how to tell true from fake AGN?"]}

TESS is not a statistical mission, but the data present a valuable opportunity for studies of exoplanet populations. In order to conduct such studies, it is essential to understand the properties of the target sample - why were specific stars selected, others excluded, using what criteria. The TESS prime mission produced light curves for the 2-min target stars, and is producing a larger light curve catalog from a subset of the stars observed at the 30-min cadence. Both sets were assembled using information from the TIC, with the bulk of the 2-min targets drawn from the ranked CTL. Here we describe the global properties of both the 2-min and 30-min sets, including their physical parameters and their observational and variability characteristics from TESS related to transit detection. We review the "K dwarf desert", the trends of photometric precision with stellar type, and the implications of the difference between the CTL population and the actual 2-min cadence population., {"references":["Stassun, Keivan et al. (2018). The TESS Input Catalog and Candidate Target List, AJ, 156, 102","Stassun, Keivan et al. (2019) The Revised TESS Input Catalog and Candidate Target List, AJ, 158, 138"]}

We report the detection of a transiting planet around π Men (HD 39091), using data from the Transiting Exoplanet Survey Satellite (TESS). The solar-type host star is unusually bright (V = 5.7) and was already known to host a Jovian planet on a highly eccentric, 5.7-year orbit. The newly discovered planet has a size of 2.04 ± 0.05 R⊕ and an orbital period of 6.27 days. Radial-velocity data from the HARPS and AAT/UCLES archives also displays a 6.27-day periodicity, confirming the existence of the planet and leading to a mass determination of 4.82±0.85 M⊕. The star's proximity and brightness will facilitate further investigations, such as atmospheric spectroscopy, asteroseismology, the Rossiter-McLaughlin effect, astrometry, and direct imaging.

We report the detection of a transiting planet around $��$ Mensae (HD 39091), using data from the Transiting Exoplanet Survey Satellite (TESS). The solar-type host star is unusually bright (V=5.7) and was already known to host a Jovian planet on a highly eccentric, 5.7-year orbit. The newly discovered planet has a size of $2.04\pm 0.05$ $R_\oplus$ and an orbital period of 6.27 days. Radial-velocity data from the HARPS and AAT/UCLES archives also displays a 6.27-day periodicity, confirming the existence of the planet and leading to a mass determination of $4.82\pm 0.85$ $M_\oplus$. The star's proximity and brightness will facilitate further investigations, such as atmospheric spectroscopy, asteroseismology, the Rossiter--McLaughlin effect, astrometry, and direct imaging., Accepted for publication ApJ Letters. This letter makes use of the TESS Alert data, which is currently in a beta test phase. The discovery light curve is included in a table inside the arxiv submission

Reverberation Mapping of AGN Accretion Disks

The interiors of giant planets remain poorly understood. Even for the planets in the Solar System, difficulties in observation lead to large uncertainties in the properties of planetary cores. Exoplanets that have undergone rare evolutionary processes provide a route to understanding planetary interiors. Planets found in and near the typically barren hot-Neptune 'desert'1,2 (a region in mass-radius space that contains few planets) have proved to be particularly valuable in this regard. These planets include HD149026b3, which is thought to have an unusually massive core, and recent discoveries such as LTT9779b4 and NGTS-4b5, on which photoevaporation has removed a substantial part of their outer atmospheres. Here we report observations of the planet TOI-849b, which has a radius smaller than Neptune's but an anomalously large mass of [Formula: see text] Earth masses and a density of [Formula: see text] grams per cubic centimetre, similar to Earth's. Interior-structure models suggest that any gaseous envelope of pure hydrogen and helium consists of no more than [Formula: see text] per cent of the total planetary mass. The planet could have been a gas giant before undergoing extreme mass loss via thermal self-disruption or giant planet collisions, or it could have avoided substantial gas accretion, perhaps through gap opening or late formation6. Although photoevaporation rates cannot account for the mass loss required to reduce a Jupiter-like gas giant, they can remove a small (a few Earth masses) hydrogen and helium envelope on timescales of several billion years, implying that any remaining atmosphere on TOI-849b is likely to be enriched by water or other volatiles from the planetary interior. We conclude that TOI-849b is the remnant core of a giant planet.