Galaxy Zoo: 3D-crowdsourced bar, spiral, and foreground star masks for MaNGA target galaxies
Monthly Notices of the Royal Astronomical Society Oxford University Press 507:3 (2021) 3923-3935
Abstract:
The challenge of consistent identification of internal structure in galaxies - in particular disc galaxy components like spiral arms, bars, and bulges - has hindered our ability to study the physical impact of such structure across large samples. In this paper we present Galaxy Zoo: 3D (GZ:3D) a crowdsourcing project built on the Zooniverse platform that we used to create spatial pixel (spaxel) maps that identify galaxy centres, foreground stars, galactic bars, and spiral arms for 29 831 galaxies that were potential targets of the MaNGA survey (Mapping Nearby Galaxies at Apache Point Observatory, part of the fourth phase of the Sloan Digital Sky Surveys or SDSS-IV), including nearly all of the 10 010 galaxies ultimately observed. Our crowdsourced visual identification of asymmetric internal structures provides valuable insight on the evolutionary role of non-axisymmetric processes that is otherwise lost when MaNGA data cubes are azimuthally averaged. We present the publicly available GZ:3D catalogue alongside validation tests and example use cases. These data may in the future provide a useful training set for automated identification of spiral arm features. As an illustration, we use the spiral masks in a sample of 825 galaxies to measure the enhancement of star formation spatially linked to spiral arms, which we measure to be a factor of three over the background disc, and how this enhancement increases with radius.Optimization of the Observing Cadence for the Rubin Observatory Legacy Survey of Space and Time: a pioneering process of community-focused experimental design
(2021)
The lens SW05 J143454.4+522850: a fossil group at redshift 0.6?
Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 506:2 (2021) 1715-1722
Planet Hunters TESS III: two transiting planets around the bright G dwarf HD 152843
Monthly Notices of the Royal Astronomical Society, Volume 505, Issue 2, August 2021, Pages 1827–1840
Abstract:
We report on the discovery and validation of a two-planet system around a bright (V = 8.85 mag) early G dwarf (1.43 R⊙, 1.15 M⊙, TOI 2319) using data from NASA’s Transiting Exoplanet Survey Satellite (TESS). Three transit events from two planets were detected by citizen scientists in the month-long TESS light curve (sector 25), as part of the Planet Hunters TESS project. Modelling of the transits yields an orbital period of 11.6264+0.0022−0.0025 d and radius of 3.41+0.14−0.12 R⊕ for the inner planet, and a period in the range 19.26–35 d and a radius of 5.83+0.14−0.14 R⊕ for the outer planet, which was only seen to transit once. Each signal was independently statistically validated, taking into consideration the TESS light curve as well as the ground-based spectroscopic follow-up observations. Radial velocities from HARPS-N and EXPRES yield a tentative detection of planet b, whose mass we estimate to be 11.56+6.58−6.14 M⊕, and allow us to place an upper limit of 27.5 M⊕ (99 per cent confidence) on the mass of planet c. Due to the brightness of the host star and the strong likelihood of an extended H/He atmosphere on both planets, this system offers excellent prospects for atmospheric characterization and comparative planetology.
A low [CII]/[NII] ratio in the center of a massive galaxy at z = 3.7: Evidence for a transition to quiescence at high redshift? (Corrigendum)
Astronomy & Astrophysics EDP Sciences 650 (2021) c2