Systematic Analysis of Language Transcripts Solutions: A Tutorial

Purpose: In the early 1980s, researchers and speech-language pathologists (SLPs) collaborated to develop the Systematic Analysis of Language Transcripts (SALT). Research and development over the ensuing decades has culminated into SALT Solutions, a set of tools to assist SLPs to efficiently complete language sample analysis (LSA) with their clients. In this tutorial, we describe how SALT can assist with the accurate identification of children with language disorders and provide a rich description of children\u27s functional language use. After summarizing the multiple elicitation methods developed by the SALT team, we provide case studies, showing how to select an elicitation method that aligns with a child\u27s characteristics. We then summarize major considerations when transcribing, analyzing, and interpreting language samples with SALT. We revisit our case studies to illustrate how SALT adds value to the comprehensive assessment of language in children. Conclusions: LSA is a powerful assessment tool for children suspected of having language disorders. The SALT suite of solutions provides a toolkit to assist SLPs with their comprehensive language assessments

Cooling of the crust in the neutron star low-mass X-ray binary MXB 1659-29

In quasi-persistent neutron star transients, long outbursts cause the neutron star crust to be heated out of thermal equilibrium with the rest of the star. During quiescence, the crust then cools back down. Such crustal cooling has been observed in two quasi-persistent sources: KS 1731-260 and MXB 1659-29. Here we present an additional Chandra observation of MXB 1659-29 in quiescence, which extends the baseline of monitoring to 6.6 yr after the end of the outburst. This new observation strongly suggests that the crust has thermally relaxed, with the temperature remaining consistent over 1000 days. Fitting the temperature cooling curve with an exponential plus constant model we determine an e-folding timescale of 465 +/- 25 days, with the crust cooling to a constant surface temperature of kT = 54 +/- 2 eV (assuming D=10 kpc). From this, we infer a core temperature in the range 3.5E7-8.3E7 K (assuming D=10 kpc), with the uncertainty due to the surface composition. Importantly, we tested two neutron star atmosphere models as well as a blackbody model, and found that the thermal relaxation time of the crust is independent of the chosen model and the assumed distance.Comment: accepted for publication in ApJL, 4 pages, 1 figure

Evidence for High-Frequency QPOs with a 3:2 Frequency Ratio from a 5000 Solar Mass Black Hole

Following the discovery of 3:2 resonance quasi-periodic oscillations (QPOs) in M82X-1 (Pasham et al. 2014), we have constructed power density spectra (PDS) of all 15 (sufficiently long) {\it XMM-Newton} observations of the ultraluminous X-ray source NGC1313X-1 ($L_{X}$ $\approx$ 2$\times$10$^{40}$ erg/sec). We detect a strong QPO at a frequency of 0.29$\pm$0.01 Hz in data obtained on 2012 December 16. Subsequent searching of all the remaining observations for a 3:2/2:3 frequency pair revealed a feature at 0.46$\pm$0.02 Hz on 2003 Dec 13 (frequency ratio of 1.59$\pm$0.09). The global significance of the 0.29 Hz feature considering all frequencies between 0.1 and 4 Hz is $>$ 3.5 $\sigma$. The significance of the 0.46$\pm$0.02 Hz QPO is $>$ 3.5$\sigma$ for a search at 2/3 and 3/2 of 0.29 Hz. We also detect lower frequency QPOs (32.9$\pm$2.6 and 79.7$\pm$1.2 mHz). All the QPOs are super-imposed on a continuum consisting of flat-topped, band-limited noise, breaking into a power-law at a frequency of 16$\pm$3 mHz and white noise at $\gtrsim$ 0.1 Hz. NGC1313X-1's PDS is analogous to stellar-mass black holes' (StMBHs) PDS in the so-called steep power-law state, but with the respective frequencies (both QPOs and break frequencies) scaled down by a factor of $\sim$ 1000. Using the inverse mass-to-high-frequency QPO scaling of StMBHs, we estimate NGC1313X-1's black hole mass to be 5000$\pm$1300 $M_{\odot}$, consistent with an inference from the scaling of the break frequency. However, the implied Eddington ratio, L$_{Edd}$ $>$ 0.03$\pm$0.01, is significantly lower compared to StMBHs in the steep power-law state (L$_{Edd}$ $\gtrsim$ 0.2).Comment: Published in ApJ Letter

An Efficient Targeting Strategy for Multiobject Spectrograph Surveys: the Sloan Digital Sky Survey "Tiling" Algorithm

Large surveys using multiobject spectrographs require automated methods for deciding how to efficiently point observations and how to assign targets to each pointing. The Sloan Digital Sky Survey (SDSS) will observe around 10 6 spectra from targets distributed over an area of about 10,000 deg2, using a multiobject fiber spectrograph that can simultaneously observe 640 objects in a circular field of view (referred to as a "tile") 1°.49 in radius. No two fibers can be placed closer than 55Prime; during the same observation; multiple targets closer than this distance are said to "collide." We present here a method of allocating fibers to desired targets given a set of tile centers that includes the effects of collisions and that is nearly optimally efficient and uniform. Because of large-scale structure in the galaxy distribution (which form the bulk of the SDSS targets), a naive covering of the sky with equally spaced tiles does not yield uniform sampling. Thus, we present a heuristic for perturbing the centers of the tiles from the equally spaced distribution that provides more uniform completeness. For the SDSS sample, we can attain a sampling rate of greater than 92% for all targets, and greater than 99% for the set of targets that do not collide with each other, with an efficiency greater than 90% (defined as the fraction of available fibers assigned to targets). The methods used here may prove useful to those planning other large surveys

Quiescent X-ray Emission From Cen X-4: A Variable Thermal Component

The nearby neutron star low-mass X-ray binary, Cen X-4, has been in a quiescent state since its last outburst in 1979. Typically, quiescent emission from these objects consists of thermal emission (presumably from the neutron star surface) with an additional hard power-law tail of unknown nature. Variability has been observed during quiescence in Cen X-4 on both timescales as short as hundreds of seconds and as long as years. However, the nature of this variability is still unknown. Early observations seemed to show it was all due to a variable hard X-ray tail. Here, we present new and archival observations that contradict this. The most recent Suzaku observation of Cen X-4 finds it in a historically low state, a factor of 4.4 fainter than the brightest quiescent observation. As the spectrum during the brightest observation was comprised of approximately 60% from the thermal component and 40% from the power-law component, such a large change cannot be explained by just power-law variability. Spectral fits with a variable thermal component fit the data well, while spectral fits allowing both the column density and the power law to vary do not, leading to the conclusion that the thermal component must be variable. Interestingly, we also find that the thermal fraction remains consistent between all epochs, implying that the thermal and power-law fluxes vary by approximately the same amount. If the emitting area remains unchanged between observations, then the effective surface temperature must change. Alternatively, if the temperature remains constant, then the emitting area must change. The nature of this thermal variability is unclear, but may be explained by variable low-level accretion

An X-Ray View of the Jet-Cycle in the Radio Loud AGN 3C120

We present a study of the central engine in the broad-line radio galaxy 3C120 using a multi-epoch analysis of a deep XMM-Newton observation and two deep Suzaku pointings (in 2012). In order to place our spectral data into the context of the disk-disruption/jet-ejection cycles displayed by this object, we monitor the source in the UV/X-ray bands, and in the radio band. We find three statistically acceptable spectral models, a disk-reflection model, a jet-model and a jet+disk model. Despite being good descriptions of the data, the disk-reflection model violates the radio constraints on the inclination, and the jet-model has a fine-tuning problem, requiring a jet contribution exceeding that expected. Thus, we argue for a composite jet+disk model. Within the context of this model, we verify the basic predictions of the jet-cycle paradigm, finding a truncated/refilling disk during the Suzaku observations and a complete disk extending down to the innermost stable circular orbit (ISCO) during the XMM-Newton observation. The idea of a refilling disk is further supported by the detection of the ejection of a new jet knot approximately one month after the Suzaku pointings. We also discover a step-like event in one of the Suzaku pointings in which the soft band lags the hard band. We suggest that we are witnessing the propagation of a disturbance from the disk into the jet on a timescale set by the magnetic field.Comment: 14 pages, 10 figures, accepted for publication in Ap

XMM-Newton observations of CYGNUS X-1

Observations of Cygnus X-1 were first attempted under this program in the spring of 2004, but were complicated by instrumental flaring problems. Successful observations were completed in the fall of 2004, and processed data were delivered to the PI in the winter and spring of 2005. Thus, focused work on this data was only possible starting in 2005. A preliminary reduction and analysis of data from the EPIC CCD cameras and the Reflection Grating Spectrometer has been made. The EPIC spectra reveal the best example of a broadened, relativistic iron emission line yet found in Cygnus X-1. The Oxygen K-shell region has been shown to be a very complex wavelength range in numerous spectra of accreting sources, but the RGS spectra reveal this region in great detail and will be important in understanding the wind from the 0-type donor star that is focused onto the black hole in Cygnus X-1

A Chandra observation of the long-duration X-ray transient KS 1731-260 in quiescence: too cold a neutron star?

After more than a decade of actively accreting at about a tenth of the Eddington critical mass accretion rate, the neutron-star X-ray transient KS 1731-260 returned to quiescence in early 2001. We present a Chandra/ACIS-S observation taken several months after this transition. We detected the source at an unabsorbed flux of ~2 x 10^{-13} erg/cm^2/s (0.5-10 keV). For a distance of 7 kpc, this results in a 0.5-10 keV luminosity of ~1 x 10^{33} erg/s and a bolometric luminosity approximately twice that. This quiescent luminosity is very similar to that of the other quiescent neutron star systems. However, if this luminosity is due to the cooling of the neutron star, this low luminosity may indicate that the source spends at least several hundreds of years in quiescence in between outbursts for the neutron star to cool. If true, then it might be the first such X-ray transient to be identified and a class of hundreds of similar systems may be present in the Galaxy. Alternatively, enhanced neutrino cooling could occur in the core of the neutron star which would cool the star more rapidly. However, in that case the neutron star in KS 1731-260 would be more massive than those in the prototypical neutron star transients (e.g., Aql X-1 or 4U 1608-52).Comment: Accepted for publicaton in ApJ letters, 13 September 200