2,816 research outputs found

    WL 17: A Young Embedded Transition Disk

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    We present the highest spatial resolution ALMA observations to date of the Class I protostar WL 17 in the ρ\rho Ophiuchus L1688 molecular cloud complex, which show that it has a 12 AU hole in the center of its disk. We consider whether WL 17 is actually a Class II disk being extincted by foreground material, but find that such models do not provide a good fit to the broadband SED and also require such high extinction that it would presumably arise from dense material close to the source such as a remnant envelope. Self-consistent models of a disk embedded in a rotating collapsing envelope can nicely reproduce both the ALMA 3 mm observations and the broadband SED of WL 17. This suggests that WL 17 is a disk in the early stages of its formation, and yet even at this young age the inner disk has been depleted. Although there are multiple pathways for such a hole to be created in a disk, if this hole were produced by the formation of planets it could place constraints on the timescale for the growth of planetesimals in protoplanetary disks.Comment: 7 pages, 3 figures, 2 tables, accepted for publication in ApJ

    Protoplanetary Disks in the Orion Nebula Cluster: Gas Disk Morphologies and Kinematics as seen with ALMA

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    We present Atacama Large Millimeter Array CO(3-2) and HCO+^+(4-3) observations covering the central 1.51\rlap{.}'5×\times1.51\rlap{.}'5 region of the Orion Nebula Cluster (ONC). The unprecedented level of sensitivity (\sim0.1 mJy beam1^{-1}) and angular resolution (\sim0.09350\rlap{.}''09 \approx 35 AU) of these line observations enable us to search for gas-disk detections towards the known positions of submillimeter-detected dust disks in this region. We detect 23 disks in gas: 17 in CO(3-2), 17 in HCO+^+(4-3), and 11 in both lines. Depending on where the sources are located in the ONC, we see the line detections in emission, in absorption against the warm background, or in both emission and absorption. We spectrally resolve the gas with 0.50.5 km s1^{-1} channels, and find that the kinematics of most sources are consistent with Keplerian rotation. We measure the distribution of gas-disk sizes and find typical radii of \sim50-200 AU. As such, gas disks in the ONC are compact in comparison with the gas disks seen in low-density star-forming regions. Gas sizes are universally larger than the dust sizes. However, the gas and dust sizes are not strongly correlated. We find a positive correlation between gas size and distance from the massive star θ1\theta^1 Ori C, indicating that disks in the ONC are influenced by photoionization. Finally, we use the observed kinematics of the detected gas lines to model Keplerian rotation and infer the masses of the central pre-main-sequence stars. Our dynamically-derived stellar masses are not consistent with the spectroscopically-derived masses, and we discuss possible reasons for this discrepancy.Comment: 42 pages, 31 figure

    Proposed Treatment Protocols for Sex Offenders Based on Sub-Typology

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    Based on the findings of Robertiello and Terry (2007) this paper evaluates similarities in sex offender sub-types and proposes grouping similar sub-types together for the purpose of treatment. Those sub-types with similar characteristics or are found to have similar responses to treatment options can be grouped together either in prison, in-patient, or out-patient settings and may prove to be more effective treatment protocols than current “one size fits all” sex offender treatment programs. This paper reviews the past 30 years of research on treatment for specific sub-types and integrates it into a larger framework while offering suggestions for future research on the efficacy of grouping these sub-types together. Finally, this review offers the suggestion of providing sexuality training to sex offenders to promote more healthy sexual interactions post treatment.No embarg

    Agrarian way

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    My thesis is really in three fold. Since my work has its origin in the recollections of my earliest childhood memories, I will explain how the pieces in my show are a result of those early memories. Next I will explore how the pieces I design are influenced by my childhood observations and experiences with farm life and agrarian equipment. Finally, I will consider the direction of my future work, and how it can continue to grow and mature

    Using transcranial direct-current stimulation (tDCS) to understand cognitive processing

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    Noninvasive brain stimulation methods are becoming increasingly common tools in the kit of the cognitive scientist. In particular, transcranial direct-current stimulation (tDCS) is showing great promise as a tool to causally manipulate the brain and understand how information is processed. The popularity of this method of brain stimulation is based on the fact that it is safe, inexpensive, its effects are long lasting, and you can increase the likelihood that neurons will fire near one electrode and decrease the likelihood that neurons will fire near another. However, this method of manipulating the brain to draw causal inferences is not without complication. Because tDCS methods continue to be refined and are not yet standardized, there are reports in the literature that show some striking inconsistencies. Primary among the complications of the technique is that the tDCS method uses two or more electrodes to pass current and all of these electrodes will have effects on the tissue underneath them. In this tutorial, we will share what we have learned about using tDCS to manipulate how the brain perceives, attends, remembers, and responds to information from our environment. Our goal is to provide a starting point for new users of tDCS and spur discussion of the standardization of methods to enhance replicability.The authors declare that they had no conflicts of interest with respect to their authorship or the publication of this article. This work was supported by grants from the National Institutes of Health (R01-EY019882, R01-EY025272, P30-EY08126, F31-MH102042, and T32-EY007135). (R01-EY019882 - National Institutes of Health; R01-EY025272 - National Institutes of Health; P30-EY08126 - National Institutes of Health; F31-MH102042 - National Institutes of Health; T32-EY007135 - National Institutes of Health)Accepted manuscrip

    A VLA Survey For Faint Compact Radio Sources in the Orion Nebula Cluster

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    We present Karl G. Janksy Very Large Array (VLA) 1.3 cm, 3.6 cm, and 6 cm continuum maps of compact radio sources in the Orion Nebular Cluster. We mosaicked 34 square arcminutes at 1.3 cm, 70 square arcminutes at 3.6 cm and 109 square arcminutes at 6 cm, containing 778 near-infrared detected YSOs and 190 HST-identified proplyds (with significant overlap between those characterizations). We detected radio emission from 175 compact radio sources in the ONC, including 26 sources that were detected for the first time at these wavelengths. For each detected source we fit a simple free-free and dust emission model to characterize the radio emission. We extrapolate the free-free emission spectrum model for each source to ALMA bands to illustrate how these measurements could be used to correctly measure protoplanetary disk dust masses from sub-millimeter flux measurements. Finally, we compare the fluxes measured in this survey with previously measured fluxes for our targets, as well as four separate epochs of 1.3 cm data, to search for and quantify variability of our sources.Comment: 13 pages, 6 figures, 4 tables, ApJ, in pres

    New Beginning

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