11 pages, 9 figures, accepted for publication by ApJ
Hot channels (HCs) are prevalent in the solar corona and play a critical role in driving flares and CMEs. In this paper, we estimate the energy contents of an X1.4 eruptive flare with a fast CME generated by a HC eruption on 2011 September 22. Originating from NOAA AR11302, the HC is the most dramatic feature in 131 and 94 {\AA} images observed by SDO/AIA. The flare is simultaneously observed by SDO/AIA, RHESSI, and STEREO-B/EUVI. The CME is simultaneously detected by the white-light coronagraphs of SOHO/LASCO and STEREO-B/COR1. Using multiwavelength and multiview observations of the eruption, various energy components of the HC, flare, and CME are calculated. The thermal and kinetic energies of the HC are (1.77$\pm$0.61)$\times10^{30}$ erg and (2.90$\pm$0.79)$\times10^{30}$ erg, respectively. The peak thermal energy of the flare and total radiative loss of SXR-emitting plasma are (1.63$\pm$0.04)$\times10^{31}$ erg and (1.03$-$1.31)$\times10^{31}$ erg, respectively. The ratio between the thermal energies of HC and flare is 0.11$\pm$0.03, suggesting that thermal energy of the HC is not negligible. The kinetic and potential energies of the CME are (3.43$\pm$0.94)$\times10^{31}$ erg and (2.66$\pm$0.49)$\times10^{30}$ erg, yielding a total energy of (3.69$\pm$0.98)$\times10^{31}$ erg for the CME. Continuous heating of the HC is required to balance the rapid cooling by heat conduction, which probably originate from intermittent magnetic reconnection at the flare current sheet. Our investigation may provide insight into the buildup, release, and conversion of energies in large-scale solar eruptions.
This article has been accepted by Astronomy & Astrophysics
The determination of the spatial geometry of the universe plays an important role in modern cosmology. Any deviation from the cosmic curvature $\Omega_K=0$ would have a profound impact on the primordial inflation paradigm and fundamental physics. In this paper, we carry out a systematic study of the prospect of measuring cosmic curvature with the inspiral signal of supermassive black hole binaries (SMBHBs) that could be detected with TianQin. The study is based on a cosmological-model-independent method that extended the application of gravitational wave (GW) standard sirens in cosmology. By comparing the distances from future simulated GW events and simulated $H(z)$ data, we evaluate if TianQin would produce robust constraints on the cosmic curvature parameter $\Omega_{k}$. More specifically, we consider 3-yr to 10-yr observations of supermassive black hole binaries with total masses ranging from $10^{3}M_\odot$ to $10^{7}M_\odot$. Our results show that in the future, with the synergy of 10-yr high-quality observations, we can tightly constrain the curvature parameter at the level of $1\sigma$ $\Omega_k=-0.002\pm0.061$. Moreover, our findings indicate that the total mass of SMBHB does influence the estimation of cosmic curvature, implied by the analysis performed on different subsamples of gravitational wave data. Therefore, TianQin is expected to provide a powerful and competitive probe of the spatial geometry of the universe, compared to future spaced-based detectors such as DECIGO.
The JWST Early Release Observations (ERO) included a NIRISS/SOSS (0.6-2.8$\,\mu$m) transit of the $\sim\,$850$\,$K Saturn-mass exoplanet HAT-P-18$\,$b. Initial analysis of these data reported detections of water, escaping helium, and haze. However, active K dwarfs like HAT-P-18 possess surface heterogeneities $-$ starspots and faculae $-$ that can complicate the interpretation of transmission spectra, and indeed, a spot-crossing event is present in HAT-P-18$\,$b's NIRISS/SOSS light curves. Here, we present an extensive reanalysis and interpretation of the JWST ERO transmission spectrum of HAT-P-18$\,$b, as well as HST/WFC3 and $\textit{Spitzer}$/IRAC transit observations. We detect H$_2$O (12.5$\,\sigma$), CO$_2$ (7.3$\,\sigma$), a cloud deck (7.4$\,\sigma$), and unocculted starspots (5.8$\,\sigma$), alongside hints of Na (2.7$\,\sigma$). We do not detect the previously reported CH$_4$ ($\log$ CH$_4$ $<$ -6 to 2$\,\sigma$). We obtain excellent agreement between three independent retrieval codes, which find a sub-solar H$_2$O abundance ($\log$ H$_2$O $\approx -4.4 \pm 0.3$). However, the inferred CO$_2$ abundance ($\log$ CO$_2$ $\approx -4.8 \pm 0.4$) is significantly super-solar and requires further investigation into its origin. We also introduce new stellar heterogeneity considerations by fitting for the active regions' surface gravities $-$ a proxy for the effects of magnetic pressure. Finally, we compare our JWST inferences to those from HST/WFC3 and $\textit{Spitzer}$/IRAC. Our results highlight the exceptional promise of simultaneous planetary atmosphere and stellar heterogeneity constraints in the era of JWST and demonstrate that JWST transmission spectra may warrant more complex treatments of the transit light source effect.
Submitted for review to the Monthly Notices of the Royal Astronomical Society. 13 pages, 16 figures
We present the characterisation of the two transiting planets around HD 152843 (TOI 2319, TIC 349488688) using an intensive campaign of HARPS-N radial velocities, and two sectors of TESS data. These data reveal a unique and fascinating system: HD 152843 b and c have near equal masses of around 9 M$_\oplus$ but differing radii of $3.05 \pm 0.11$ R$_\oplus$ and $5.94^{+0.18}_{-0.16}$ R$_\oplus$ , respectively, and orbital periods of $11.62071^{+9.6e-05}_{-0.000106}$ days and $19.502104^{+7.4e-05}_{-8.5e-05}$ days. This indicates that HD 152843 c is in the lowest fifth percentile in density of the known exoplanet population, and has the longest orbital period among these low density planets. Further, HD 152843 c's radius places it in the Saturn valley, the observed lack of planets larger than Neptune, but smaller than Saturn. The orbital periods of these planets indicate they are near a 5:3 mean motion resonance, indicating the possibility of transit timing variations, and hints at the possibility of interaction with a third planet at some point in the evolution of this system. Further, the brightness of the host star and the low density of HD 152843 c make it a key target for atmospheric characterisation.
18 pages, 6 figures, Accepted by the Astrophysical Journal Letters
We report the discovery of two TESS sub-Neptunes orbiting the early M dwarf TOI-904 (TIC 261257684). Both exoplanets, TOI-904 b and c, were initially observed in TESS sector 12 with twin sizes of 2.49R$_\oplus$ and 2.31R$_\oplus$, respectively. Through observations in five additional sectors in the TESS primary mission and the first and second extended missions, the orbital periods of both planets were measured to be 10.887$\pm$0.001 and 83.999$\pm$0.001 days, respectively. Reconnaissance radial velocity measurements (taken with EULER/CORALIE) and high resolution speckle imaging with adaptive optics (obtained from SOAR/HRCAM and Gemini South/ZORRO) show no evidence of an eclipsing binary or a nearby companion, which together with the low false positive probabilities calculated with the statistical validation software TRICERATOPS establish the planetary nature of these candidates. The outer planet, TOI-904 c, is the longest-period M dwarf exoplanet found by TESS, with an estimated equilibrium temperature of 217K. As the three other validated planets with comparable host stars and orbital periods were observed by Kepler around much dimmer stars (J$_{mag}$ $>$ 12), TOI-904 c, orbiting a brighter star (J$_{mag}$ $=$ 9.6), is the coldest M dwarf planet easily accessible for atmospheric follow-up. Future mass measurements and transmission spectroscopy of the similar sized planets in this system could determine whether they are also similar in density and composition, suggesting a common formation pathway, or whether they have distinct origins.
19 pages, 13 figures, accepted for publication in A&A
23 pages, 12 figures, submitted to A&A. Comments welcome!
10 pages, no figs, to be published in Phys. Rev. D
15 pages, 15 figures, submitted to A&A
22 pages, 11 figures
13 pages, 8 figures. Accepted to ApJ Letters
6 pages, 8 figures. Accepted for publication in A&A
18 pages, 16 figures
11 pages, 10 figures
9 pages, 5 figures. Accepted for publication in Contrib. Astron. Obs. Skalnate Pleso (Invited lecture at V Meeting on Astrophysical Spectroscopy - A&M DATA 2023)
10 pages, 6 figures, ICRC2023 Conference Proceedings
16 pages, 6 figures, 3 tables, submitted to ApJ
2 pages, 2 figures; a reproducible article prepared with ShowYourWork hosted at this https URL
Accepted to The Astrophysical Journal Supplement
White Paper for the Line Emission Mapper Astrophysics APEX X-ray Probe
30 pages, 7 figures, 2 tables
14 pages, 10 figures, 2 tables
6 pages, 4 figures, 2 tables, accepted to be published in MNRAS Letters
35 pages, 34 figures
12 pages, 6 figures, 4 tables, Accepted for publication on Monthly Notices of the Royal Astronomical Society
To be submitted to ApJL. Comments and feedback welcome
Accepted in ApJ
14 pages, 12 figures, accepted for publication in Astronomy & Astrophysics
4 pages, 1figure
11 pages, 9 figures. Submitted to MNRAS
Submitted to MNRAS Letter on September 29th. Comments are welcome. 8 pages, 1 table, 3 figures, and 1 beautiful schematic figure in the appendix
Submitted to MNRAS on September 29th, 10 pages, 5 figures, comments are welcome
27 pages, 22 figures, and 11 tables
26 pages, 2 Figures. Bases on a talk presented at the "MOND at 40'' conference at St' Andrews University, July 2023
Accepted for publication as a Letter in Astronomy and Astrophysics
20 pages, 7 Figures, 1 Table, Submitted to ApJ Letters
Submitted to A&A Letter
11 pages, 6 figures
13 pages, 10 figures, Adaptive Optics for Extremely Large Telescopes 7th Edition, 25-30 Jun 2023 Avignon (France)
To be published in The Planetary Science Journal, 51 pages, 34 figures, 4 tables
17 pages, 18 figures, Submitted to MNRAS
9 pages, 6 figures
8 figures, 2 tables, Accepted for publication in ApJ
4 pages, 1 figure, submitted to RNAAS
28 pages, 9 figures and 7 Tables. Submitted to MNRAS
14 pages, 8 figures, resubmitted to ApJ following moderate revision
22 pages, 13 figures, 1 table. Accepted for publication in Publications of the Astronomical Society of Japan
28 pages, 19 figures, submitted to ApJ
9 pages, 2 figures, 2 columns
26 pages and 17 figures
31 pages, 24 figures, 3 tables, accepted for publication by A&A
19 pages, 13 figures; Accepted for publication in A&A
6 pages, 3 figures, 1 table, submitted to MNRAS (revised version), comments welcome!
13 pages, 7 figures, accepted for publication in MNRAS
Invited review at 2022 RR Lyrae and Cepheids conference on La Palma, 9 pages, 2 figures
13 pages, 9 figures, 1 table, accepted for publication in ApJ
12 pages, 2 figures, submitted to PASA
14 pages, 9 figures, submitted to A&A
Accepted for publication by the Astrophysical Journal
Resubmitted to Nature Astronomy, 6 main figures, 7 extended figures, and 2 extended tables
accepted by PASP
14 pages, 9 figures and 7 tables, accepted for publication in Physics and Astronomy Reports
Re-submitted to MNRAS following moderate review, 23 October 2023
35 pages, 5 figures
Submitted to AJ. Missing citations welcome
12 pages, 7 figures, accepted for publication in A&A
24 pages, 17 figures
22 pages, 16 figures, accepted 2023 September 7, published 2023 September 29
Progress of Theoretical and Experimental Physics accepted version
Submitted to MNRAS journal. Associated catalog of high precision, Cannon-rederived abundances for GALAH solar twins to be made publicly available upon acceptance and available now upon request. See Manea et al. 2023 for a complementary, high precision, Cannon-rederived abundance catalog for GALAH red giant stars
Accepted to MNRAS. 12 pages, 11 figures
7 figures, accepted to Nature
13 pages, 10 figures, plus Appendices, submitted to MNRAS
8 pages, 5 figures
7 pages, 4 figures
13 pages, 1 table, 5 figures. Article published in Physical Review D,
21 pages, 14 figures
LaTex2e, 13 pages, 4 figures, 1 table. arXiv admin note: text overlap with arXiv:2310.02834
Accepted for publication in ApJ, 17 pages, 10 figures
28 pages, 2 figures
5 pages, 2 figures. arXiv admin note: text overlap with arXiv:2212.00198
31 pages + 2 appendices
17 pages; 6 figures
This paper is an invited contribution to the Special Issue "Recent Advances in Gravity: A Themed Issue in Honor of Prof. Jorge Pullin on his 60th Anniversary''
Comments welcomed