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Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac324c
Impact craters are present on all bodies in the solar system with many displaying complex interior morphologies such as central peaks and central pits. Central peaks form due to the uplift of material in the center of the crater during transient crater formation while central pit formation has been suggested to occur by a number of processes including impacts into a weaker target which may contain volatiles. Comparing central peaks and central pits on rocky bodies like the Moon and Vesta will provide information about the formation processes of these morphologies on volatile poor bodies. In this study, we surveyed 248 craters on the Moon and Vesta. Our study of these central pits and central peaks suggest that crustal strength may contribute to the formation of central pits on rocky bodies and supports the notion that volatiles may not contribute to the formation of central pits on rocky bodies.
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac3255
HD 41004 is an unusual multiple star/planet system. Recent TESS photometry revealed a striking 31 hr period, far too short for the slowly rotating K dwarf primary. Instead, the modulation likely is from the diminutive dM secondary, spun-up to synchronous rotation by its close-in brown dwarf companion, and suffering intense magnetic activity as a result. If so, the red dwarf is perhaps destined to someday return the favor by cannibalizing its substellar partner.
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac3253
In this note, I report a R-band polarimetric study on a massive star-forming region GL 437 (a.k.a. AFGL 437) to infer the magnetic field (B-field) geometry of this region. The mean B-field in the diffused region, is found to be parallel to the extended cloud structure and the Galactic plane. I compared present optical polarization results with archival submm results adapted from Curran & Chrysostomou. A flipped field geometry is seen in denser parts of GL 437 which is an interesting finding. An infrared source WK 34 embedded in the cloud is associated with a poorly collimated outflow. These outflows are parallel to the inner field orientation but misaligned with outer B-fields. An investigation of gas kinematics of this region will be carried out to understand if the gas motion have some role in changing the field geometry.
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac3256
We report second-timescale infrared photometry of the nova V1674 Her using Palomar Gattini-IR (PGIR). These observations constitute the first infrared and highest temporal resolution data (resolution of ≈0.84 s) of the nova reported to date. PGIR observed in this fast readout mode for more than an hour on three nights between 3 and 6 days after discovery. We searched for periodic variability using a Lomb–Scargle periodogram and did not detect anything down to a three sigma upper limit of 0.093 mag. This suggests that the periodic variability detected in the nova by Patterson et al. was lower by at least a factor of about 1.65 in the first week of the eruption.
The Astrophysical Journal, Volume 921; https://doi.org/10.3847/2041-8213/ac2ee7
The repeating fast radio burst FRB 20200120E is located in a globular cluster belonging to the nearby M81 galaxy. Its small distance (3.6 Mpc) and accurate localization make it an interesting target to search for bursting activity at high energies. From 2003 November to 2021 September, the INTEGRAL satellite has obtained an exposure time of 18 Ms on the M81 sky region. We used these data to search for hard X-ray bursts from FRB 20200120E using the IBIS/ISGRI instrument, without finding any significant candidate, down to an average fluence limit of ∼10−8 erg cm−2 (20–200 keV). The corresponding limit on the isotropic luminosity for a burst of duration Δt is erg s−1, the deepest limit obtained for an extragalactic FRB in the hard X-ray range. This rules out the emission of powerful flares at a rate higher than 0.1 yr−1 that could be expected in models invoking young hyperactive magnetars.
The Astrophysical Journal, Volume 921; https://doi.org/10.3847/2041-8213/ac2ee4
The unusual multiwavelength lightcurves of GRB 101225A are revisited by assuming that they are from an off-axis GRB powered by a newborn magnetar. We show that GRB 101225A's optical afterglow lightcurve is fitted with the forward shock model by parameterizing its jet structure as a Gaussian function with a half-opening angle of the jet core as 167. The derived initial Lorentz factor (Γ0) is 120, and the viewing angle to the jet axis is θv = 37. Tentative QPO signatures of P = 488 s and P = 250 ∼ 300 s are found with a confidence level of 90% by analyzing its X-ray flares observed in the time interval of [4900, 7500] s. Its global gamma-ray/X-ray lightcurve and the QPO signatures are represented with the magnetar dipole radiation (DR) model by considering the magnetar precession motion, assuming that the magnetar spindown is dominated by GW emission. The bulk Lorentz factor of the DR ejecta is limited to 8, being much lower than Γ0. Comparing GRB 101225A with the extremely off-axis GRB 170817A, we suspect that the nature of the two-component jet in GRB 170817A is a combination of a co-axial GRB jet and a DR ejecta. GRB 101225A would be among the brightest ones of the CDF-S XT2-like X-ray transient population driven by newborn magnetars. A discussion of the detectability of its gravitational wave emission is also presented.
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac313e
Quenching is the process by which a galaxy's star formation ceases and it moves from being a blue star-forming to a red quiescent galaxy. Concentration has been shown to be a good indicator of this process; this paper uses ΔΣ1 (a concentration offset derived below) to observe how quenching differs between galaxy morphologies. We use Sloan Digital Sky Survey data to plot ΔSFR against ΔΣ1, with morphological classifications from Galaxy Zoo 2 and environmental classifications from Yang et al. We find a difference in the distributions of concentration offset between early- and late-types that is not observed with differing environmental conditions and so conclude that separating the two allows more insight into their individual quenching processes. Late-types are shown to follow a process of compaction before then quenching and this is consistent with a picture where they quench slower than the early-types.
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac3086
Orbital resonance phenomena are notoriously difficult to communicate in words due to the complex dynamics arising from the interplay of gravity and orbital angular momentum. A well known example is Pluto's 3:2 mean motion resonance with Neptune. We have developed a python software tool to visualize the full three-dimensional aspects of Pluto's resonant orbital dynamics over time. The visualizations include still images and animated movies. By contrasting Pluto's resonant dynamics with the dynamics of a nearby non-resonant orbit, this tool enables better understanding and exploration of complex planetary dynamics phenomena.
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac2502
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac224d
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac20d6
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac1e93
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac2431
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac2ef0
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac2eef
We showcase a tool suite that enables the fitting of soft X-ray spectra in active galactic nuclei (AGNs), without the need for specialist software, allowing access to AGN physics for school students. While these standardized Python tools were useful for measuring velocities, they offered significantly fewer capabilities for radiative recombination continua, and R and G ratios, utilized to obtain the internal plasma properties within the outflowing wind seen in NGC 4151. Although further work is required for these tools to be used in outreach projects, we present findings of the plasma temperature and density in NGC 4151 spanning a 15 yr period.
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac18cd
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac2eee
We use Gaia EDR3 astrometry to propose that a dynamical interaction between the multiple system θ1 Ori C and θ1 Ori F ejected the latter as a walkaway star ∼1100 yr ago (without deceleration) or somewhat later (with a more likely deceleration included). It is unclear whether the final 3D velocity of θ1 Ori F will be large enough to escape the Orion nebula cluster.
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac1a71
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac19ba
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac1744
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac2e6c
Two follow up observing sessions of Kepler's Eclipsing Binary star system EPIC 201458798 (from the K2 mission) were conducted in the Spring of 2018 and 2019 utilizing the 0.4 m subnet of the Los Cumbres Observatory Global Telescope network. The total duration of observations for each session (∼77 days) was comparable with the duration of observations by the Kepler telescope ∼80 days. 900–1000 images were obtained during each session with an integrating time around 1 minute, resulting in about 800 mag measurements per session. In contrast, the Kepler telescope provided almost continuous measurements of this star with an integration time per image of about 30 minutes, resulting in about 3250 photometric points. In contrast to the Kepler telescope measurements, which were conducted with one very broad filter, the observations in this study used four filters: B, V, ip, and rp. This data was processed and the period, time of minimum, and depth of the eclipses was determined. The results were compared with the data obtained by the Kepler telescope and other historical records.
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac17f6
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac18bf
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac0bc6
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac1ff8
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac2de7
The comparison of far-ultraviolet spectra taken years apart with the IUE shows that the FUV flux of HR 4138 is variable. An abundance analysis of High Accuracy Radial velocity Planet Searcher spectra reveals that the light elements (with Z less than 30) have solar or nearly solar abundances whereas heavier elements are overabundant. Inspection of the Transiting Exoplanet Survey Satellite lightcurves of HR 4138 suggests that the rotational period of HR 4138 may be close to 3 days.
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac2df8
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac1f97
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac22b1
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac2de8
We present the first results from the SuperWASP Variable Stars (SVS) citizen science project. The photometry archive of the Wide Angle Search for Planets has previously been searched for periodic variations and the results of this search formed the basis of the SVS project on the Zooniverse. The SVS project asks volunteers to visually inspect light curve plots and categorize each one according to a broad classification scheme. Results from the first two years of SVS have now been published online as the SuperWASP Variable Star Photometry Archive (VeSPA). The archive can be browsed online, downloaded in full, or queried, filtered, and sorted to export a refined set of results. An interactive light curve viewer also allows any light curve to be folded at a user-defined period. Analysis of citizen science results and development of VeSPA features are both ongoing. Updated results will be published every six months.
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac2df2
We present the discovery of what appears to be both a uniquely cool and old white dwarf (WD) within 30 pc of the Sun. DES J214756.46-403529.3 is detected in four separate surveys, 50° away from the Galactic Plane. The combination of its very low luminosity and spectral energy distribution suggests an object unlike any other astrophysical body currently known. Among 8000 of the nearest single objects in the immediate solar neighborhood, it appears completely isolated in multiple color–magnitude diagrams. The data seem compatible with an extremely old and cool WD with a helium dominated atmosphere and a mass around 0.7–0.8 M⊙ but spectroscopic follow-up is required to confirm its nature.
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac2d33
In 2017, the first image of the center of the M87 galaxy was captured by the Event Horizon Telescope (EHT). It revealed a ring morphology and a size consistent with theoretical expectations for the light pattern around a weakly accreting supermassive black hole of ∼6.5 billion solar masses. In parallel to the EHT measurements, an extensive multi-wavelength (MWL) campaign with ground- and space-based facilities from radio all the way up to the TeV energy range was organized. In this note we will give an overview of the results from this campaign. M87 was found to be in a historically low state. At X-ray energies the emission from the core dominates over HST-1. We present the most complete simultaneous, MWL spectrum of the active nucleus to date.
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac2d35
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac2d34
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac2d37
Star formation involves gravity, turbulence, magnetic fields, and feedback from new stars through jets, radiation and winds. The evolution of the density probability distribution function (ρ-PDF) is directly related to the star formation rate (SFR), forming the basis of several star formation models. We utilize two runs from the STARFORGE simulation suite that follow the evolution of molecular clouds, while resolving individual stars and including all gas and feedback physics. The two runs have different initial conditions, one is a periodic box with driven turbulence (Box), while the other is an isolated cloud without turbulent driving (Sphere). We find that the ρ-PDF for both runs is initially well-fit by a log-normal (LN) plus a power-law (PL) function. However, as the SFR peaks, the PDF for the Sphere run becomes well-fit by just a wide LN. Conversely, the Box run PDF remains well-fit by a LN+PL function for the entirety of the run.
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac1593
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac1798
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac2d38
The comparison of a coadded International Ultraviolet Explorer (IUE) far-ultraviolet spectrum of 21 Com (A3p SrCr) to that of the standard star α Psa (A3V) reveals large differences in the resonance and low-excitation lines of C i and Al ii. All the lines of these species are significantly weaker in the mean spectrum of 21 Com. The synthesis of these lines consistently yields sizable underabundances for 21 Com of about 0.5 times the solar carbon, and 0.20 times solar for aluminum. Inspection of 10 individual spectra taken over the 24 hr monitoring of 21 Com with IUE on 1991 April 17 does not reveal convincing variations of the lines analyzed here between rotational phases 0.18 and 0.65 of the 2 days period, suggesting a uniform repartition of these 2 elements over the hemisphere of 21 Com observed then.
Research Notes of the AAS, Volume 5; https://doi.org/10.3847/2515-5172/ac2d36
This Research Note summarizes preliminary results, presented at the 238th AAS meeting, for the K-band luminosity functions (LFs) of IllustrisTNG300-1 galaxies. For MK ≥ −22, the simulation reproduces both the shape and amplitude of the LF for observed field galaxies. However, it significantly overproduces field galaxies with MK < −22. For MK ≤ −22, the simulation reproduces the shape of the LF for observed cluster galaxies, however at fainter magnitudes the LF falls below a simple extrapolation of recent observations. For MK ≤ −22, the shapes of the LFs for red cluster galaxies and blue cluster galaxies agree reasonably well with observations, but neither is well-fitted by a Schechter function at fainter magnitudes. In addition, the faint-end slope of the LF in the inner regions of the clusters is significantly flatter than it is in the outer regions.
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac042e
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac116b
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac1f1e
Luminous Red Variables are most likely eruptions that are the outcome of stellar mergers. V838 Mon is one of the best-studied members of this class, representing an archetype for stellar mergers resulting from B-type stars. As result of the merger event, "nova-like" eruptions occur driving mass loss from the system. As the gas cools considerable circumstellar dust is formed. V838 Mon erupted in 2002 and is undergoing very dynamic changes in its dust composition, geometry, and infrared luminosity providing a real-time laboratory to validate mineralogical condensation sequences in stellar mergers and evolutionary scenarios. We discuss recent NASA Stratospheric Observatory for Infrared Astronomy 5–38 μm observations combined with archival NASA Spitzer spectra that document the temporal evolution of the freshly formed (within the last ≲20 yr) circumstellar material in the environs of V838 Mon. Changes in the 10 μm spectral region are strong evidence that we are witnessing a classical dust condensation sequence expected to occur in oxygen-rich environments where alumina formation is followed by that of silicates at the temperature cools.
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac1f8f
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac1582
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac174c
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac134a
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac1da7
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac179c
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac082a
The Astronomical Journal, Volume 162; https://doi.org/10.3847/1538-3881/ac1584