V893 Sco is an ordinary dwarf nova, with a narrow eclipse that allows for exact timings of minima. These eclipse times have been used to seek variations (compared to a linear ephemeris) by placement onto a traditional O−C diagram. Bruch collected 114 eclipse times from 1999 to 2013, and noted that the residuals in his O−C diagram had an apparent sinusoidal variation with a period of 10.2 yr. After

Galaxy clusters are extremely over dense regions of the universe and are therefore ideal for testing how galaxy properties vary with environment. We analyze a sample of >3000 galaxy spectra from 100 galaxy cluster fields, and examine trends in redshift, Dn4000, and a formulated in-fall proxy for member and non-member galaxies. The 4000 Å break (Dn4000) reveals information about the age of each galaxy

We address in this work the instrumental systematic errors that can potentially affect the forthcoming and future Cosmic Microwave Background experiments aimed at observing its polarized emission. In particular, we focus on the systematics induced by the beam and calibration, which are considered the major sources of leakage from total intensity measurements to polarization. We simulated synthetic

We present X-ray analysis of three short Chandra observations of M87. The basis of this analysis is the search for possible new ultraluminous X-ray sources (ULXs) in M87's globular clusters (GCs) and attempt to quantify possible variability within the observations. We searched Chandra ObsIDs 1808 (2000 July 30, 14 ks) Wilson & Yang, 3975 (2002 November 17, 5 ks) and 3977 (2003 February 4, 5 ks) Harris

The International Astronomical Youth Camp (IAYC) is an astronomy education outreach event with more than 50 yr of history and over 1700 unique participants from 81 nationalities. The International Workshop for Astronomy e.V. is the non-profit organization behind the IAYC, established in 1979 and based in Germany. The IAYC’s unprecedented longevity in a rapidly globalizing world has meant that financial

We investigate the orientation of the photospheric magnetic fields in the solar polar region using observations from the Helioseismic and Magnetic Imager (HMI). Inside small patches of significant polarization, the inferred magnetic field vectors at 1″ scale appear to systematically deviate from the radial direction. Most tilt toward the pole; all are more inclined toward the plane of sky compared

The mission of the 2000 kg Cassini spacecraft concluded on 2017 September 15, by its deliberate entry into Saturn’s atmosphere at some 31.1 km s−1. Observations, using Hubble and groundbased observatories, to attempt optical detection of this 0.25 kT “artificial meteor” are summarized. No signatures were identified. A challenge with observing the event is that due to atmospheric drag, its timing was

1RXS J180431.1-273932 is an intermediate polar: a cataclysmic variable star with a rapidly rotating, magnetized white dwarf. We analyze the system’s Kepler K2 short-cadence light curve and identify a strong, highly coherent pulse with a period of 0.00571710.0000002days, which matches the proposed white dwarf rotational period identified in previous X-ray studies. We establish an ephemeris for the optical

We present time resolved low resolution spectra of BLAP-009 and BLAP-014 collected with SPRAT on the Liverpool Telescope. The spectra were median-stacked in four ranges of phase. It was intended to note the variation in the shape of the helium absorption lines as a function of phase, but they do not appear to vary with time in low resolution spectra. The lack of clear offsets in the absorption lines

We present V and I photometry for the Be/X-ray binary Swift J010745.0-722740 taken in 1997–2020. The data show recurring outbursts, with an amplitude up to 0.4 mag and an improved orbital period of 1180.0 0.3 days. The light curve during outburst has a double-peaked profile, with a rapid rise and gradual decline. The effective temperature of the outburst region is ∼6200 K, much cooler than that of

Stars in multiple systems offer a unique opportunity to learn about stellar formation and evolution. As they settle down into stable configurations, multiple systems occur in a variety of hierarchies and a wide range of separations between the components. We examine 11 known and 11 newly discovered multiple systems including at least one M dwarf with the latest astrometric data from Gaia Early Data

Nulling pulsars are pulsars whose observed flux occasionally disappears, but the mechanism behind the cessation is not well understood. Motivated by the correlation between pulse width and nulling fraction found in Sheikh & MacDonald, we compile all 378 nulling pulsars to date with their pulse widths in a machine-readable table. We also include the observing frequency and time resolution of each pulse

Population synthesis studies of binary black hole mergers often lack robust black hole spin estimates as they cannot accurately follow tidal spin-up during the late black hole–Wolf–Rayet evolutionary phase. We provide an analytical approximation of the dimensionless second-born black hole spin given the binary orbital period and Wolf–Rayet stellar mass at helium depletion or carbon depletion. These

Lyα photons from the first radiating sources in the universe play a pivotal role in 21 cm radio detections of Cosmic Dawn and the Epoch of Reionization. Comments are provided on the effect of the hyperfine structure of hydrogen on the rate of heating or cooling of the Intergalactic Medium by Lyα photons.

We summarize results of an XMM-Newton X-ray observation of the WN8h-type Wolf–Rayet star WR 66 which shows unusual 3.5–4.1 hr optical variations. One possible explanation is a compact companion (cc) which, if present, could give rise to luminous X-ray emission. WR 66 was marginally detected and its inferred X-ray luminosity (L x ) is orders of magnitude below that expected from wind accretion onto

This study aims to contribute to the astronomical studies for the creation of the astronomical and archaeological museum in Ecuador. Coaque, a fishermen village in the north coastal of Ecuador, is an iconic place where astronomy and archeology converge and portrays the geodesic and astronomical history of Ecuador. The 16th Century ethnohistorical data is rich on descriptions about abundance of wealth

We re-examine the XUV luminosity evolution of TRAPPIST-1 utilizing new observational constraints (XUV and bolometric luminosity) from multi-epoch X-ray/UV photometry. Following the formalism presented in Fleming et al., we infer that TRAPPIST-1 maintained a saturated XUV luminosity, relative to the bolometric luminosity, of log10(L XUV/L bol) at early times for a period of t sat Gyr. After the saturation

Type IIn supernovae (SNe IIn) are an enigmatic subclass of SNe that show heterogeneity in their photometric and spectroscopic properties. Complex, multi-component Balmer line profiles are a defining property of SNe IIn. Perhaps owing to the heterogeneity in the SN IIn class, online databases often conflict and hold outdated or erroneous classifications. This is compounded by SN “impostors” and H ii

We present infrared spectroscopy from two epochs of V1533 Scorpii (=Nova Scorpii 2013); one from immediately before dust formation and a second, from one month later when dust formation was complete. The pre-dust spectrum shows strong lines of C i, features that weakened considerably but were still present after dust formation. Also present in the post-formation spectrum was O i emission from the neutral

For several years we have been running an “astro-animation” class (AstroAnimation.org) at the Maryland Institute College of Art (MICA) in Baltimore where students work in tandem with research scientists from NASA Goddard and elsewhere to create animations. These combine results of cutting-edge research with an artist’s eye to create novel presentations of scientific results. The animations have been

Recoiling active galactic nuclei (AGNs) can be formed after the merging of two galaxies and their central supermassive black holes. A novel method recently revealed a handful of recoiling AGN candidates. We report on the arcsec-scale radio structure of one of them, 4C 18.47, a prominent radio emitter. We also present its infrared light curve, indicating significant long-term variability.

In light of recently revised observational measurements of the radius and spectroscopic parameters of the extremely old and metal-poor Gaia benchmark star HD 140283—also known as the Methuselah star due to prior suggestions that its age is in tension with the age of the universe—we present new, best estimates for the star’s mass and age from stellar modeling. These are derived using 1D stellar evolutionary

We present new physical properties for an extreme (L IR > 1013 L ⊙), unlensed dusty star-forming galaxy at z = 4.531, G09-81106. We compile fluxes from the literature, and include new Hubble Space Telescope data to generate SED models under various assumptions. G09-81106 has a number of physical characteristics that far surpass the average data for DSFGs, including high dust temperature (∼70 K) and

The ultra-wideband low (UWL) receiver is a new feed for the Parkes telescope, which covers the combined bandwidth of four previously installed receivers. In order to use the UWL for technosignature observations, several updates and upgrades were made on the Breakthrough Listen Parkes Data Recorder (BLPDR). This Research Note summarizes BLPDR hardware upgrades and new capacity for technosignature observations

X-ray spectral fitting of astronomical sources requires convolving the intrinsic spectrum or model with the instrumental response. Standard forward modeling techniques have proven success in recovering the underlying physical parameters in moderate to high signal-to-noise regimes; however, they struggle to achieve the same level of accuracy in low signal-to-noise regimes. Additionally, the use of machine

We present photometric B, V, and R observations of the semiregular variable V698 Tau taken in 2020–2021. The star varies by ∼1 mag in each filter with a mean period of ∼185 days. At minimum light the star is noticeably redder in V − R than at maximum while slightly bluer in B − V. The magnitudes and colors are consistent with those of a reddened M8 giant.

Most asteroids are somewhat elongated and have non-zero lightcurve amplitudes. Such asteroids can be detected in large-scale sky surveys even if their mean magnitudes are fainter than the stated sensitivity limits. We explore the detection of elongated asteroids under a set of idealized but useful approximations. We find that objects up to 1 mag fainter than a survey’s sensitivity limit are likely

We report 14 radial velocities for three field stars located near the RR Lyrae variables NO Cas, NR Lyr, and V1176 Sgr. We identified the three field stars using Gaia Early Data Release 3. Two of these stars confirm the Gaia radial velocities. The third has no previously published radial velocity.

We report a new period mid-infrared variability of PMN J0948+0022 on 2020 April 26, observed by the Wide-field Infrared Survey Explore (WISE). This source faded consistently over a period of one day. The amplitude of variability is about 0.21 and 0.18 mag in the W1 (3.4 μm) and W2 (4.6 μm) bands, respectively. The intraday variability constrains the size of the mid-infrared emission region to about

We use a combination of Hipparcos space mission data with the USNO dedicated ground-based astrometric program URAT-Bright designed to complement and verify Gaia results for the brightest stars in the south to estimate the small perturbations of observed proper motions caused by exoplanets. One of the 1423 bright stars in the program, δ Pav, stands out with a small proper motion difference between our

Gaussian processes (GPs) are used widely in the analysis of astronomical time series. GPs with rational spectral densities have state-space representations which allow evaluation of the likelihood. We calculate analytic state space representations for the damped simple harmonic oscillator and the Matrn 1/2, 3/2 and 5/2 processes.

We revisit Wagoner et al., a classic contribution in the development of Big Bang Nucleosynthesis. We demonstrate that it presents an incorrect expression for the temperature of the early universe as a function of time in the high temperature limit, K. As this incorrect expression has been reproduced elsewhere, we present a corrected form for the initial conditions required for calculating the formation

The intrinsic nature of many astronomical objects, such as binary systems, exoplanets, circumstellar disks, and quasar host galaxies, introduces challenging requirements on observational instrumentation and techniques. In each case, we encounter situations where the light from bright sources completely outshines the surrounding faint targets. As a result, we are yet to fully understand the processes

Abundances for 20 chemical elements are derived for Maia, the fourth brightest member of the Pleiades, using updated atomic data. Maia does not seem to be a typical helium-weak star nor a classical HgMn star. Instead Maia might be related to the phosphorus and gallium-rich stars.

Cumulative hardness comparisons are a simple but statistically powerful test for the presence of gravitational lensing in gamma-ray bursts (GRBs). Since gravitational lensing does not change photon energies, all source images should have the same spectra—and hence hardness. Applied to the recent claim that the two pulses in GRB 950830 are lensed images of the same pulse, the measured flux ratio between

We present a simple but informative online tool to visualize the multiwavelength (MW) properties of ≈2700 X-ray sources from Chandra Source Catalog version 2.0 with literature verified classifications. Here we describe the catalogs that we used to collect the classifications and extract the MW properties of these sources, and the properties themselves. We also describe the design and functionality

Radio-loud quasars (RLQs) are known to produce excess X-ray emission, compared to radio-quiet quasars (RQQs) of the same luminosity, commonly attributed to jet-related emission. Recently, we found that the He ii EW and α ox in RQQs are strongly correlated, which suggests that their extreme-ultraviolet (EUV) and X-ray emission mechanisms are tightly related. Using 48 RLQs, we show that steep-spectrum

Using data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) Survey, we examined a subsample of 29 E+A galaxy candidates in the Coma Cluster. We created spatially-resolved maps of spectral features and the kinematics of the underlying stellar population by utilizing the Marvin toolkit. We rule out star formation in the entire subsample, and do not find evidence for AGN activity.

deepCR is a deep-learning-based cosmic-ray rejection algorithm previously demonstrated to be superior to state-of-the-art LACosmic on Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS)/WFC F606W imaging data. In this research note, we present a new deepCR model for use on all filters of HST ACS/WFC. We train and test the model with ACS/WFC F435W, F606W, and F814W images, covering the entire

We report on the processes and findings related to the iterative design of the San Antonio Teacher Training Astronomy Academy (SATTAA). In particular, we show how the initial iteration in 2018, limited to only future (or preservice) secondary school STEM teachers, broadened to include current (or in-service) secondary school teachers in 2019, and then added primary school pre- and in-service teachers

We report the preliminary near- and mid-infrared 3D radiative transfer simulations of the carbon-rich AGB star RUVir using the 3D radiative transfer code RADMC-3D. We found that the inclusion of molecular and dust species reproduces the extended atmosphere of this star well. This study is the beginning of an in-progress effort toward a more systematic 3D radiative transfer modeling of RUVir’s extended

The Simons Observatory is a Cosmic Microwave Background experiment to observe the microwave sky in six frequency bands from 30 to 290 GHz. The Observatory—at ∼5200m altitude—comprises three Small Aperture Telescopes and one Large Aperture Telescope (LAT) at the Atacama Desert, Chile. This research note describes the design and current status of the LAT along with its future timeline.

Galaxy mergers are a mechanism for rapid quenching of star formation. We are studying E+A galaxies (a type of post-starburst galaxy) and how they are impacted by merging. Examining E+A galaxies with companions offers insight into the evolution of E+As and the quenching process. The Y/Dim Collaboration collected a sample of E+A candidate galaxies from the SDSS DR16. Among the E+A candidates that were

For many generations, the Maya people of the highlands of Guatemala have been engaged in continual knowledge creation emerging from a deep and sustained relationship with the Earth and the sky. Maya elders and youth who are Calendar Keepers, or Ajq’ijab’ in the K’iche’ Mayan language, curate calendars with roots in pre-colonial times. The pressures of colonial invasion, civil war, and globalization

The Sun, Moon, planets, and stars have accompanied sky watchers over millennia. The Pleiades star cluster, observable from every continent except Antarctica, is tied to Indigenous worldviews, astronomy, calendaring, traditional weaving, weather prediction, and agriculture. The heliacal rising of the cluster—its first visible sighting in the morning twilight before sunrise, is particularly significant

In this research note, we present linemake, an open-source atomic and molecular line list generator. Rather than a replacement for a number of well-established atomic and molecular spectral databases, linemake aims to be a lightweight, easy-to-use tool to generate formatted and curated lists suitable for spectral synthesis work. We encourage users of linemake to understand the sources of their transition

In the last decade, exoplanets space missions started to collect a huge amount of photometric observations, with over ∼1,000,000 new light curves generated every month from the Transiting Exoplanet Survey Satellite (TESS) full-frame images alone. In order to analyze such an unprecedented volume of data, automated planet-candidate detection has become an appreciable replacement to human vetting. In

We present 46 HW Virginis Post-Common Envelope Binary Systems identified by the Zwicky Transient Facility, 26 of which appear to be new discoveries. Through the application of the Box Least-Squares Algorithm to ZTF data, we searched a data set of 17,473 systems for periodicity and phase-folded all of the ZTF lightcurves of the objects at their best period. Through visual analysis of these phase-folded

In the current picture of cosmology and astrophysics, the formation and evolution of galaxies is closely linked to that of their dark matter haloes. The best representation of this galaxy-dark matter halo co-evolution is the relation. In this study we investigate how the radio-mode feedback from active galactic nuclei (AGN) affects the relation at redshifts 0.08

The Comet Interceptor Mission (ESA/JAXA) aims to visit a long-period comet or interstellar object. Its primary science goals are to characterize the object's shape, structure, and the composition of its surface and gas coma. The mission consists of three spacecraft, the primary and two accompanying ones. The focus of this paper is the unique synergetic activities between two mass spectrometers to investigate

We compare features from the circulation model developed in Stȩpień for contact binaries to a long-term hydrodynamical evolution of a symmetric contact binary. The numerical evolution is fully three-dimensional and begins from an equilibrium structure in contact at one grid cell. As the evolution is conducted with Flow-ER, an explicit hydrodynamics code for self-gravitating fluids, we are not able

We present low-resolution spectra collected with the Spectral Energy Distribution Machine (SEDM) for an IW And-type dwarf nova, HO Puppis, and a Be star, V722 Tauri. The SEDM is an integrated field unit spectrograph mounted on the 60 inch telescope at the Palomar Observatory, with a spectral resolution of R ∼ 100 in the optical wavelength range. The Hα emission line was clearly detected for the bright

Coma Berenices (Coma Ber), an open cluster about the same age as Praesepe and the Hyades (700–800 Myr) is, despite being only 85 pc away, less well studied than its famous cousins. This is due principally to its sparseness and low proper motion, which together made Coma Ber’s membership challenging to establish pre-Gaia. We have curated a new list of its members based on Gaia DR2 astrometry, derived

In the study of large astronomical data sets, virtual reality (VR) can help build valuable spatial intuition for scientific discovery. We created VR visualizations of E+A galaxies and candidates in four nearby clusters of galaxies: Leo, Virgo, Hercules, and Coma. E+A's are a type of post-starburst galaxy in which all star formation has been recently (∼1 Gyr ago) quenched. Our E+A samples were assembled

Mechanical feedback from young massive stars in super star clusters contributes to the formation of superwinds and superbubbles in star-forming regions. We conduct hydrodynamic simulations using the non-equilibrium ionization package maihem to explore how outflow velocity, mass-loading, metallicity, and ambient density can affect the occurrence of catastrophic cooling. To predict optical and UV emission

Evidence is presented that the far ultraviolet flux of Maia recorded by the International Ultraviolet Explorer is variable over a timescale of a few hours. In contrast, the radial velocity of the Si ii doublet near 1530 Å does not vary on short timescales.

We are conducting a survey of high-resolution near-infrared CO rovibrational spectra in protoplanetary disks around young intermediate-mass stars. We use IRTF-iSHELL with the 0.″375 and 0.″75 slits, providing 4 km s−1 and 6km s−1 resolution and covering 4.52–5.25μm in one single exposure. This includes part of the rovibrational R branch and most of the P branch of the CO fundamental band (Δv=1), one

Exoplanets are planets that orbit stars other than our Sun, and the most common way of detecting them is by the transit method. This method consists of plotting the relative brightness of the exoplanets host star against a comparison star to make what is known as a light curve. Periodic dips in the light curve could correspond to the exoplanet coming in front of its host star, and blocking some of

We are conducting a multi-wavelength analysis of high-resolution molecular spectra that probe the evolution of gas in the inner 10au in protoplanetary disks. A sample of 15 disks has been combined to probe a range of inner disk structures including small and large dust cavities. Half of the sample has been observed in far-ultraviolet H2 emission with a new HST-COS program (GO-14703), that we have combined

Symplectic integrators are widely used for the study of planetary dynamics and other N-body problems. In a study of the outer solar system, we demonstrate that individual symplectic integrations can yield biased errors in the semimajor axes and possibly other orbital elements. The bias is resolved by studying an ensemble of initial conditions of the outer solar system. Such statistical sampling could