Investigating the Disk–Jet Structure in M87 through Flux Separation in the Linear and Circular Polarization Images
Abstract

For testing different electron temperature (Te) prescriptions in general relativistic magnetohydrodynamics (GRMHD) simulations through observations, we propose to utilize linear polarization (LP) and circular polarization (CP) images. We calculate the polarization images based on a semi-magnetically arrested disk GRMHD model for variousTeparameters, bearing M87 in mind. We find an LP–CP separation in the images of the low-Tedisk cases at 230GHz; namely, the LP flux mainly originates from downstream of the jet, and the CP flux comes from the counter-side jet, while the total intensity is maximum at the jet base. This can be understood as follows: although the LP flux is generated through synchrotron emission widely around the black hole, most of the LP flux from the jet base does not reach the observer, since it undergoes Faraday rotation ($∝Te−2$) when passing through the outer cold disk and is thus depolarized. Hence, only the LP flux from the downstream (not passing the cold dense plasmas) can survive. Meanwhile, the CP flux is generated from the LP flux by Faraday conversion ( ∝Te) in the inner hot region. Stronger CP flux is thus observed from the counter-side jet. Moreover, the LP–CP separation is more enhanced at more »

Authors:
; ; ; ; ;
Award ID(s):
Publication Date:
NSF-PAR ID:
10367378
Journal Name:
The Astrophysical Journal
Volume:
931
Issue:
1
Page Range or eLocation-ID:
Article No. 25
ISSN:
0004-637X
Publisher:
DOI PREFIX: 10.3847
National Science Foundation
##### More Like this
1. Abstract

We present the discovery of the first millimeter afterglow of a short-durationγ-ray burst (SGRB) and the first confirmed afterglow of an SGRB localized by the GUANO system on Swift. Our Atacama Large Millimeter/Sub-millimeter Array (ALMA) detection of SGRB 211106A establishes an origin in a faint host galaxy detected in Hubble Space Telescope imaging at 0.7 ≲z≲ 1.4. From the lack of a detectable optical afterglow, coupled with the bright millimeter counterpart, we infer a high extinction,AV≳ 2.6 mag along the line of sight, making this one of the most highly dust-extincted SGRBs known to date. The millimeter-band light curve captures the passage of the synchrotron peak from the afterglow forward shock and reveals a jet break at$tjet=29.2−4.0+4.5$days. For a presumed redshift ofz= 1, we infer an opening angle,θjet= (15.°5 ± 1.°4), and beaming-corrected kinetic energy of$log(EK/erg)=51.8±0.3$, making this one of the widest and most energetic SGRB jets known to date. Combining all published millimeter-band upper limits in conjunction with the energetics for a large sample of SGRBs, we find that energetic outflows in high-density environments are more likely to have detectable millimeter counterparts. Concerted afterglow searches with ALMA shouldmore »

2. Abstract

We compare 500 pc scale, resolved observations of ionized and molecular gas for thez∼ 0.02 starbursting disk galaxy IRAS08339+6517, using measurements from KCWI and NOEMA. We explore the relationship of the star-formation-driven ionized gas outflows with colocated galaxy properties. We find a roughly linear relationship between the outflow mass flux ($Σ̇out$) and star formation rate surface density (ΣSFR),$Σ̇out∝ΣSFR1.06±0.10$, and a strong correlation between$Σ̇out$and the gas depletion time, such that$Σ̇out∝tdep−1.1±0.06$. Moreover, we find these outflows are so-calledbreakoutoutflows, according to the relationship between the gas fraction and disk kinematics. Assuming that ionized outflow mass scales with total outflow mass, our observations suggest that the regions of highest ΣSFRin IRAS08 are removing more gas via the outflow than through the conversion of gas into stars. Our results are consistent with a picture in which the outflow limits the ability of a region of a disk to maintain short depletion times. Our results underline the need for resolved observations of outflows in more galaxies.

3. A theoretical analysis on crack formation and propagation was performed based on the coupling between the electrochemical process, classical elasticity, and fracture mechanics. The chemical potential of oxygen, thus oxygen partial pressure, at the oxygen electrode-electrolyte interface ($μO2OE∣El$) was investigated as a function of transport properties, electrolyte thickness and operating conditions (e.g., steam concentration, constant current, and constant voltage). Our analysis shows that: a lower ionic area specific resistance (ASR),$riOE,$and a higher electronic ASR ($reOE$) of the oxygen electrode/electrolyte interface are in favor of suppressing crack formation. The$μO2OE∣El,$thus local pO2, are sensitive towards the operating parameters under galvanostatic or potentiostatic electrolysis. Constant current density electrolysis provides better robustness, especially at a high current density with a high steam content. While constant voltage electrolysis leads to greater variations of$μO2OE∣El.$Constant current electrolysis, however, is not suitable for an unstable oxygen electrode because$μO2OE∣El$can reach a very high value with a gradually increased$riOE.$A crack may only occur under certain conditions when$pO2TPB>pcr.$

4. Abstract

We measure the molecular-to-atomic gas ratio,Rmol, and the star formation rate (SFR) per unit molecular gas mass, SFEmol, in 38 nearby galaxies selected from the Virgo Environment Traced in CO (VERTICO) survey. We stack ALMA12CO (J= 2−1) spectra coherently using Hivelocities from the VIVA survey to detect faint CO emission out to galactocentric radiirgal∼ 1.2r25. We determine the scale lengths for the molecular and stellar components, finding a ∼3:5 relation compared to ∼1:1 in field galaxies, indicating that the CO emission is more centrally concentrated than the stars. We computeRmolas a function of different physical quantities. While the spatially resolvedRmolon average decreases with increasing radius, we find that the mean molecular-to-atomic gas ratio within the stellar effective radiusRe,Rmol(r<Re), shows a systematic increase with the level of Hi, truncation and/or asymmetry (HIperturbation). Analysis of the molecular- and the atomic-to-stellar mass ratios withinRe,$R⋆mol(rand$R⋆atom(r, shows that VERTICO galaxies have increasingly lower$R⋆atom(rfor larger levels of HIperturbation (compared to field galaxies matched in stellar mass), but no significant change in$R⋆mol(r. We also measure a clear systematic decrease of the SFEmolwithinRe, SFEmol(r<Re),more »

5. Abstract

We present the latest and most precise characterization of the architecture for the ancient (≈11 Gyr) Kepler-444 system, which is composed of a K0 primary star (Kepler-444 A) hosting five transiting planets and a tight M-type spectroscopic binary (Kepler-444 BC) with an A–BC projected separation of 66 au. We have measured the system’s relative astrometry using the adaptive optics imaging from Keck/NIRC2 and Kepler-444 A’s radial velocities from the Hobby-Eberly Telescope and reanalyzed relative radial velocities between BC and A from Keck/HIRES. We also include the Hipparcos-Gaia astrometric acceleration and all published astrometry and radial velocities in an updated orbit analysis of BC’s barycenter. These data greatly extend the time baseline of the monitoring and lead to significant updates to BC’s barycentric orbit compared to previous work, including a larger semimajor axis ($a=52.2−2.7+3.3$au), a smaller eccentricity (e= 0.55 ± 0.05), and a more precise inclination ($i=85.°4−0.°4+0.°3$). We have also derived the first dynamical masses of B and C components. Our results suggest that Kepler-444 A’s protoplanetary disk was likely truncated by BC to a radius of ≈8 au, which resolves the previously noticed tension between Kepler-444 A’s disk mass and planet masses. Kepler-444more »