Abstract This study analyzes spectra from the central region of the galaxy cluster A85 observed with Gran Telescopio Canarias (GTC)/OSIRIS, focusing on the cD galaxy Holm 15A and the point-like X-ray source SDSS J004150.75-091824.3, projected 13 . ″ 74 from Holm 15A. For the latter, we found it is a background quasar with a redshift of 1.56386 ± 0.00397, ruling out the possibility of it being a rogue BH gravitationally bound to Holm 15A. In addition, using single-epoch spectroscopy, we report that the quasar J004150 hosts a Supermassive black hole (SMBH) with a mass of log ( M BH / M ⊙ ) = 8.72 ± 0.26 .
Abstract W. Wang et al. reported that the orbital period of the hot Jupiter WASP-22 b is shrinking by 71.8 ± 17.1 ms yr −1 . At that rate, 2026 transits would arrive 8.8 minutes earlier than a constant-period ephemeris fitted to the refereed 2006–2018 times predicts. I measured 14 transit times from TESS Sectors 105–107 and re-measured 5 from Sector 4 (2018). The 2026 transits arrive 1.3 ± 1.2 minutes early, consistent with a constant period. A quadratic ephemeris fitted to all 28 times gives dP / dt = −18 ± 7 ms yr −1 , or −6 ± 8 ms yr −1 without two season-averaged times from 2006 to 2007. The reported rate is excluded at 7.3 σ , or 2.6 σ –2.9 σ allowing for its published uncertainty. A constant acceleration at the rate seen in 2008–2009 radial velocities (RVs) is excluded at 5 σ or more. The remaining curvature is consistent with, but does not establish, the light-travel effect of the companion’s curving RV trend.
Abstract We investigate the evolution of the cosmic molecular gas mass density from z = 1–5 using ALMA 2 mm observations from the Ex-MORA survey combined with the COSMOS2025 catalog. Cold molecular gas fuels star formation and plays a central role in galaxy evolution, so measuring its evolution across cosmic time provides insight into galaxy evolution properties. At high redshifts ( z > 3), the distribution of cold molecular gas remains uncertain due to observational difficulties. To combat this, we apply an inverse-variance weighted stacking analysis to 780,944 mass-selected galaxies spanning z ∼ 1–5 and stellar masses down to log ( M * / M ⊙ ) ∼ 10 . This approach probes dust continuum emission below individual detection thresholds and enables measurements of molecular gas mass across redshift and mass bins. We derive the corresponding gas mass density and compare our results with existing CO- and dust-based results. Overall, we find systematically lower gas mass densities than previous studies, likely reflecting differences in our calibration and sample selection.
Abstract The abundances of the lanthanides, osmium, platinum, gold and bismuth are derived for the HgMn star HD 89822 using spectrum synthesis. The following excesses/deficiencies are found: cerium (+2.00 dex), praseodymium (+2.23), neodymium (+1.81), samarium (+2.30), europium (+2.00), gadolinium (+2.00), terbium (+3.23), dysprosium (+2.00), holmium (0.00 upper limit), erbium (+0.00 upper limit), ytterbium (+0.00 upper limit), osmium (+2.48), platinum (+4.40), gold (+4.70) and bismuth (+3.00). These are the first abundance measurements for the lanthanides in HD 89822. The abundance pattern from helium to bismuth is characteristic of that of a cool HgMn star.
Abstract Rubin Data Preview 2 (DP2) samples the CLAS+ changing-look AGN (CLAGN) candidates ∼1000–9000 days after their comparison epochs, so it can test whether these objects retain enhanced short-term optical variability after their spectral transitions. Comparing peak-to-peak amplitude in magnitudes against a photometrically quiescent quasar control, one band at a time, we do not detect a significant median-amplitude excess for any state (turn-on, turn-off, intermediate) in either of two bands, nor a different in the median ∣Δmag∣ as function of time lag. The r -band CLAS+ amplitude distributions are wider than the control’s, with the intermediate state formally significant after multiple-comparison correction. This could hint for a high-amplitude subpopulation.
