M dwarfs are common host stars to exoplanets but often lack atmospheric abundance measurements. Late-M dwarfs are also good analogs to the youngest substellar companions, which share similar
- Award ID(s):
- 1926576
- NSF-PAR ID:
- 10446897
- Publisher / Repository:
- IOP Publishing
- Date Published:
- Journal Name:
- Journal of Neural Engineering
- Volume:
- 20
- Issue:
- 4
- ISSN:
- 1741-2560
- Format(s):
- Medium: X Size: Article No. 046037
- Size(s):
- ["Article No. 046037"]
- Sponsoring Org:
- National Science Foundation
More Like this
-
Abstract T eff∼ 2300–2800 K. We present atmospheric analyses for the M7.5 companion HIP 55507 B and its K6V primary star with Keck/KPIC high-resolution (R ∼ 35,000)K -band spectroscopy. First, by including KPIC relative radial velocities between the primary and secondary in the orbit fit, we improve the dynamical mass precision by 60% and find , putting HIP 55507 B above the stellar–substellar boundary. We also find that HIP 55507 B orbits its K6V primary star with au ande = 0.40 ± 0.04. From atmospheric retrievals of HIP 55507 B, we measure [C/H] = 0.24 ± 0.13, [O/H] = 0.15 ± 0.13, and C/O = 0.67 ± 0.04. Moreover, we strongly detect13CO (7.8σ significance) and tentatively detect (3.7σ significance) in the companion’s atmosphere and measure and after accounting for systematic errors. From a simplified retrieval analysis of HIP 55507 A, we measure and for the primary star. These results demonstrate that HIP 55507 A and B have consistent12C/13C and16O/18O to the <1σ level, as expected for a chemically homogeneous binary system. Given the similar flux ratios and separations between HIP 55507 AB and systems with young substellar companions, our results open the door to systematically measuring13CO and abundances in the atmospheres of substellar or even planetary-mass companions with similar spectral types. -
Abstract We present13CO(
J = 1 → 0) observations for the EDGE-CALIFA survey, which is a mapping survey of 126 nearby galaxies at a typical spatial resolution of 1.5 kpc. Using detected12CO emission as a prior, we detect13CO in 41 galaxies via integrated line flux over the entire galaxy and in 30 galaxies via integrated line intensity in resolved synthesized beams. Incorporating our CO observations and optical IFU spectroscopy, we perform a systematic comparison between the line ratio and the properties of the stars and ionized gas. Higher values are found in interacting galaxies compared to those in noninteracting galaxies. The global slightly increases with infrared colorF 60/F 100but appears insensitive to other host-galaxy properties such as morphology, stellar mass, or galaxy size. We also present azimuthally averaged profiles for our sample up to a galactocentric radius of 0.4r 25(∼6 kpc), taking into account the13CO nondetections by spectral stacking. The radial profiles of are quite flat across our sample. Within galactocentric distances of 0.2r 25, the azimuthally averaged increases with the star formation rate. However, Spearman rank correlation tests show the azimuthally averaged does not strongly correlate with any other gas or stellar properties in general, especially beyond 0.2r 25from the galaxy centers. Our findings suggest that in the complex environments in galaxy disks, is not a sensitive tracer for ISM properties. Dynamical disturbances, like galaxy interactions or the presence of a bar, also have an overall impact on , which further complicates the interpretations of variations. -
Abstract We present measurements of the rest-frame UV spectral slope,
β , for a sample of 36 faint star-forming galaxies atz ∼ 9–16 discovered in one of the deepest JWST NIRCam surveys to date, the Next Generation Deep Extragalactic Exploratory Public Survey. We use robust photometric measurements for UV-faint galaxies (down toM UV∼ −16), originally published in Leung et al., and measure values of the UV spectral slope via photometric power-law fitting to both the observed photometry and stellar population models obtained through spectral energy distribution (SED) fitting withBagpipes . We obtain a median and 68% confidence interval forβ from photometric power-law fitting of and from SED fitting, for the full sample. We show that when only two to three photometric detections are available, SED fitting has a lower scatter and reduced biases than photometric power-law fitting. We quantify this bias and find that after correction the median . We measure physical properties for our galaxies withBagpipes and find that our faint ( ) sample is low in mass ( ), fairly dust-poor ( mag), and modestly young ( yr) with a median star formation rate of . We find no strong evidence for ultrablue UV spectral slopes (β ∼ −3) within our sample, as would be expected for exotically metal-poor (Z /Z ⊙< 10−3) stellar populations with very high Lyman continuum escape fractions. Our observations are consistent with model predictions that galaxies of these stellar masses atz ∼ 9–16 should have only modestly low metallicities (Z /Z ⊙∼ 0.1–0.2). -
Abstract We compare 500 pc scale, resolved observations of ionized and molecular gas for the
z ∼ 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 ( ) and star formation rate surface density (ΣSFR), , and a strong correlation between and the gas depletion time, such that . Moreover, we find these outflows are so-calledbreakout outflows, 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. -
Abstract The Makani galaxy hosts the poster child of a galactic wind on scales of the circumgalactic medium. It consists of a two-episode wind in which the slow, outer wind originated 400 Myr ago (Episode I;
R I= 20 − 50 kpc) and the fast, inner wind is 7 Myr old (Episode II;R II= 0 − 20 kpc). While this wind contains ionized, neutral, and molecular gas, the physical state and mass of the most extended phase—the warm, ionized gas—are unknown. Here we present Keck optical spectra of the Makani outflow. These allow us to detect hydrogen lines out tor = 30–40 kpc and thus constrain the mass, momentum, and energy in the wind. Many collisionally excited lines are detected throughout the wind, and their line ratios are consistent with 200–400 km s−1shocks that power the ionized gas, withv shock=σ wind. Combining shock models, density-sensitive line ratios, and mass and velocity measurements, we estimate that the ionized mass and outflow rate in the Episode II wind could be as high as those of the molecular gas: and yr−1. The outer wind has slowed, so that yr−1, but it contains more ionized gas,M ⊙. The momentum and energy in the recent Episode II wind imply a momentum-driven flow (p “boost” ∼7) driven by the hot ejecta and radiation pressure from the Eddington-limited, compact starburst. Much of the energy and momentum in the older Episode I wind may reside in a hotter phase, or lie further into the circumgalactic medium.