Abstract Palomar Gattini-IR (PGIR) is a wide-field, synoptic infrared time domain survey covering ≈15,000 sq. deg. of the accessible sky at ≈1–3 night cadence to a depth ofJ≈ 13.0 and ≈14.9 Vega mag in and outside the Galactic plane, respectively. Here, we present the first data release ofJ-band light curves of Two Micron All Sky Survey (2MASS) sources within the survey footprint covering approximately the first four years of operations. We describe the construction of the source catalog based on 2MASS point sources, followed by exposure filtering criteria and forced PSF photometry. The catalog contains light curves of ≈286 million unique sources with 2MASS magnitudes ofJ< 15.5 mag, with a total of ≈50 billion photometric measurements and ≈20 billion individual source detections at signal-to-noise-ratio > 3. We demonstrate the photometric fidelity of the catalog by (i) quantifying the magnitude-dependent accuracy and uncertainty of the photometry with respect to 2MASS and (ii) comparing against forced PGIR aperture photometry for known variable sources. We present simple filtering criteria for selecting reliable photometric measurements as well as examplePythonnotebooks for users. This catalog is one of the largest compilation of nightly cadence, synoptic infrared light curves to date, comparable to those in the largest optical surveys, providing a stepping stone to upcoming infrared surveys in the coming decade.
more »
« less
Multi-band Tractor Forced Photometry and Redshifts in the CDFS and XMM-LSS Fields
Abstract We present a catalog of multi-band forced photometry in the CDFS and XMM-LSS fields. We used The Tractor image-modeling software to produce de-blended photometry across 13 to 15 optical/infrared bands and determine photometric redshifts. Our catalog, which is publicly available on IRSA, contains ∼1.5 million sources and covers a total area of ∼9 deg 2 .
more »
« less
- Award ID(s):
- 2106990
- PAR ID:
- 10431281
- Date Published:
- Journal Name:
- Research Notes of the AAS
- Volume:
- 7
- Issue:
- 2
- ISSN:
- 2515-5172
- Page Range / eLocation ID:
- 33
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Magnetic cataclysmic variables (CVs) are luminous Galactic X-ray sources, which have been difficult to find in purely optical surveys due to their lack of outburst behavior. The eROSITA telescope on board the Spektr-RG mission is conducting an all-sky X-ray survey and recently released the public eROSITA Final Equatorial Depth Survey (eFEDS) catalog. We crossmatched the eFEDS catalog with photometry from the Zwicky Transient Facility and discovered two new magnetic CVs. We obtained high-cadence optical photometry and phase-resolved spectroscopy for each magnetic CV candidate and found them both to be polars. Among the newly discovered magnetic CVs is eFEDS J085037.2+044359/ZTFJ0850+0443, an eclipsing polar with orbital period P orb = 1.72 hr and WD mass M WD = 0.81 ± 0.08 M ⊙ . We suggest that eFEDS J085037.2+044359/ZTFJ0850+0443 is a low magnetic field strength polar, with B WD ≲ 10 MG. We also discovered a non-eclipsing polar, eFEDS J092614.1+010558/ZTFJ0926+0105, with orbital period P orb = 1.47 hr and magnetic field strength B WD = 36–42 MG.more » « less
-
Abstract Sub-subgiant stars (SSGs) fall below the subgiant branch and/or red of the giant branch in open and globular clusters, an area of the color–magnitude diagram (CMD) not populated by standard stellar evolution tracks. One hypothesis is that SSGs result from rapid rotation in subgiants or giants due to tidal synchronization in a close binary. The strong magnetic fields generated inhibit convection, which in turn produces large starspots, radius inflation, and lower-than-expected average surface temperatures and luminosities. Here we cross-reference a catalog of active giant binaries (RS CVns) in the field with Gaia EDR3. Using the Gaia photometry and parallaxes, we precisely position the RS CVns in a CMD. We identify stars that fall below a 14 Gyr, metal-rich isochrone as candidate field SSGs. Out of a sample of 1723 RS CVn, we find 448 SSG candidates, a dramatic expansion from the 65 SSGs previously known. Most SSGs have rotation periods of 2–20 days, with the highest SSG fraction found among RS CVn with the shortest periods. The ubiquity of SSGs among this population indicates that SSGs are a normal phase in evolution for RS CVn-type systems, not rare by-products of dynamical encounters found only in dense star clusters as some have suggested. We present our catalog of 1723 active giants, including Gaia photometry and astrometry, and rotation periods from the Transiting Exoplanet Survey Satellite and International Variable Star Index (VSX). This catalog can serve as an important sample to study the impacts of magnetic fields in evolved stars.more » « less
-
Abstract We construct a catalog of star clusters from Hubble Space Telescope images of the inner disk of the Triangulum Galaxy (M33) using image classifications collected by the Local Group Cluster Search, a citizen science project hosted on the Zooniverse platform. We identify 1214 star clusters within the Hubble Space Telescope imaging footprint of the Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER) survey. Comparing this catalog to existing compilations in the literature, 68% of the clusters are newly identified. The final catalog includes multiband aperture photometry and fits for cluster properties via integrated light spectral energy distribution fitting. The cluster catalog’s 50% completeness limit is ∼1500 M ☉ at an age of 100 Myr, as derived from comprehensive synthetic cluster tests.more » « less
-
Abstract We present NIRCam and NIRISS modules for DOLPHOT, a widely used crowded-field stellar photometry package. We describe details of the modules including pixel masking, astrometric alignment, star finding, photometry, catalog creation, and artificial star tests. We tested these modules using NIRCam and NIRISS images of M92 (a Milky Way globular cluster), Draco II (an ultrafaint dwarf galaxy), and Wolf–Lundmark–Mellote (a star-forming dwarf galaxy). DOLPHOT’s photometry is highly precise, and the color–magnitude diagrams are deeper and have better definition than anticipated during original program design in 2017. The primary systematic uncertainties in DOLPHOT’s photometry arise from mismatches in the model and observed point-spread functions (PSFs) and aperture corrections, each contributing ≲0.01 mag to the photometric error budget. Version 1.2 of WebbPSF models, which include charge diffusion and interpixel capacitance effects, significantly reduced PSF-related uncertainties. We also observed minor (≲0.05 mag) chip-to-chip variations in NIRCam’s zero-points, which will be addressed by the JWST flux calibration program. Globular cluster observations are crucial for photometric calibration. Temporal variations in the photometry are generally ≲0.01 mag, although rare large misalignment events can introduce errors up to 0.08 mag. We provide recommended DOLPHOT parameters, guidelines for photometric reduction, and advice for improved observing strategies. Our Early Release Science DOLPHOT data products are available on MAST, complemented by comprehensive online documentation and tutorials for using DOLPHOT with JWST imaging data.more » « less