Constraining the Sub-AU-Scale Distribution of Hydrogen and Carbon Monoxide Gas around Young Stars with the Keck Interferometer

We present Keck Interferometer observations of T Tauri and Herbig Ae/Be stars with a spatial resolution of a few milliarcseconds and a spectral resolution of ~2000. Our observations span the K-band, and include the Br gamma transition of Hydrogen and the v=2-0 and v=3-1 transitions of carbon monoxide. For several targets we also present data from Keck/NIRSPEC that provide higher spectral resolution, but a seeing-limited spatial resolution, of the same spectral features. We analyze the Br gamma emission in the context of both disk and infall/outflow models, and conclude that the Br gamma emission traces gas at very small stellocentric radii, consistent with the magnetospheric scale. However some Br gamma-emitting gas also seems to be located at radii of >0.1 AU, perhaps tracing the inner regions of magnetically launched outflows. CO emission is detected from several objects, and we generate disk models that reproduce both the KI and NIRSPEC data well. We infer the CO spatial distribution to be coincident with the distribution of continuum emission in most cases. Furthermore the Br gamma emission in these objects is roughly coincident with both the CO and continuum emission. We present potential explanations for the spatial coincidence of continuum, Br gamma, and CO overtone emission, and explore the implications for the low occurrence rate of CO overtone emission in young stars. Finally, we provide additional discussion of V1685 Cyg, which is unusual among our sample in showing large differences in emitting region size and spatial position as a function of wavelength.Comment: Accepted for publication in MNRA

Forests on the Edge: Forest Restoration and Concepts of Nature in Northern New Mexico

Dozens of catastrophic forest fires have impacted New Mexican communities over the last two decades, threatening humans, property, and livelihoods. Ecologically, forest systems are stressed by historically unprecedented tree density, drought, increased temperature, and dwindling ecological diversity, further increasing fire danger. An increasingly common response to these threats is to actively manage New Mexico’s forests using mechanical tree thinning and prescribed fire, with a goal of “restoring” forests to a healthier ecological state. Restoring forests is both a scientific and cultural act. While the science is well studied, land managers often struggle to understand how human values impact forest restoration decisions, and how those values differ from one community to the next. This paper examines a restoration project in La Cueva, New Mexico, a community that is debating whether and how to restore forests near their homes. Qualitative interviews with La Cueva residents and forestry professionals reveal that conflicting concepts of “nature” influence how individuals define successful forest restoration and beliefs about what (if anything) should be done to manage nearby forests

‘Care-less whispers’ in the academy during COVID-19: A feminist collaborative autoethnography

This collaborative autoethnography (Bochner and Ellis, 2016) has created a space for three women academics from working-class heritage, navigating the liminal and temporal space of the COVID-19 pandemic within a post-1992 Higher Education Institution, to explore the social relations of one Higher Education Institution and confront their lived experiences. The stories shared in this paper are analysed through a ‘care-less’ (Rogers, 2017) lens, which asks the academy to recognise and confront the duplicity and self-glorification of policy and practice, that might be viewed as acts of normalising and supporting care-less cultures and behaviours. The paper raises questions about social justice, diversity and inclusion, the intersectionality of class and gender, and the inequity of the lived experiences from those who sit on the margins. The paper is the first collaborative writing project from a newly formed staff network of academics who come from working-class backgrounds, and we are intentional in our commitment to support each other as new researchers, giving agency in support of the other to find their voice

Far Infrared Variability of Sagittarius A*: 25.5 Hours of Monitoring with HerschelHerschel

Variable emission from Sgr~A*, the luminous counterpart to the super-massive black hole at the center of our Galaxy, arises from the innermost portions of the accretion flow. Better characterization of the variability is important for constraining models of the low-luminosity accretion mode powering Sgr~A*, and could further our ability to use variable emission as a probe of the strong gravitational potential in the vicinity of the $4\times10^{6}\mathrm{M}_{\odot}$ black hole. We use the \textit{Herschel} Spectral and Photometric Imaging Receiver (SPIRE) to monitor Sgr~A* at wavelengths that are difficult or impossible to observe from the ground. We find highly significant variations at 0.25, 0.35, and 0.5 mm, with temporal structure that is highly correlated across these wavelengths. While the variations correspond to $<$1% changes in the total intensity in the \textit{Herschel} beam containing Sgr~A*, comparison to independent, simultaneous observations at 0.85 mm strongly supports the reality of the variations. The lowest point in the light curves, $\sim$0.5 Jy below the time-averaged flux density, places a lower bound on the emission of Sgr~A* at 0.25 mm, the first such constraint on the THz portion of the SED. The variability on few hour timescales in the SPIRE light curves is similar to that seen in historical 1.3 mm data, where the longest time series is available, but the distribution of variations in the sub-mm do not show a tail of large-amplitude variations seen at 1.3 mm. Simultaneous X-ray photometry from XMM-Newton shows no significant variation within our observing period, which may explain the lack of very large variations if X-ray and submillimeter flares are correlated.Comment: Accepted for publication in Ap