3,718 research outputs found
The Structure of Dense Gas in Perseus and Serpens: CLASSy Results
We present results of a dendrogram analysis of N2H+ J=1-0 data cubes from the CARMA Large Area Star-formation Survey (CLASSy). Dendrogram tree structures are characterized by their morphology and kinematics relative to one another, and provide a useful mechanism for analyzing the hierarchy of molecular regions from core-to-cloud spatial scales. Our CARMA data, with 7" spatial and 0.15 km/sec velocity resolution, yield the following results: (1) trees are more hierarchical in regions of high star formation activity; (2) in all regions, the leaf and branch morphology is widely varying and mostly not circularly symmetric; (3) there is evidence for multiple velocity components along a line of sight in only a small fraction of the mapped areas. We compare the identified N2H+ dendrogram tree structures to Herschel maps of dust emission and to Spitzeridentified young stellar object distributions to compare the dense gas distribution to the current star formation activity.Fil: Mundy, Lee G.. University of Maryland; Estados UnidosFil: Storm, Shaye. University of Maryland; Estados UnidosFil: Fernandez Lopez, Manuel. Provincia de Buenos Aires. GobernaciĂłn. ComisiĂłn de Investigaciones CientĂficas. Instituto Argentino de RadioastronomĂa. Consejo Nacional de Investigaciones CientĂficas y TĂŠcnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto Argentino de RadioastronomĂa; ArgentinaFil: Lee, Katherine. University of Illinois; Estados UnidosFil: Looney, Leslie. University of Illinois; Estados UnidosFil: Teuben, Peter J.. University of Maryland; Estados UnidosFil: Rosolowsky, Erik. University of Alberta; CanadĂĄFil: Shirley, Yancy L.. University of Arizona; Estados UnidosFil: Arce, Hector G.. Yale University; Estados UnidosFil: Plunkett, Adele. Yale University; Estados UnidosFil: Isella, Andrea. Caltech; Estados Unidos223th meeting of the American Astronomical SocietyWashingtonEstados UnidosAmerican Astronomical Societ
Dendrogram Analysis of Large-Area CARMA Images in Perseus: the Dense Gas in NGC 1333, Barnard 1, and L1451
We present spectral line maps of the dense gas across 400 square arcminutes of the Perseus Molecular Cloud, focused on NGC 1333, Barnard 1, and L1451. We constructed these maps as part of the CARMA Large Area Star-formation Survey (CLASSy), which is a CARMA key project that connects star forming cores to their natal cloud environment. This is achieved by leveraging CARMA's high angular resolution, imaging capability, and high efficiency at mosaicing large areas of the sky. CLASSy maps capture the structure and kinematics of N2H+, HCN, and HCO+ J=1-0 emission from thousand AU to parsec scales in three evolutionarily distinct regions of Perseus (in addition to two regions in Serpens). We show results from a non-binary dendrogram analysis of the Perseus N2H+ emission, which answers questions about the turbulent properties of the dense gas across evolutionary stages and across the range of size scales probed by CLASSy. There is a flat relation between mean internal turbulence and structure size for the dense gas in NGC 1333 and Barnard 1, but the magnitude of internal turbulence increases with nearby protostellar activity; the dense gas in the B1 main core and NGC 1333, which have active young stars, are characterized by mostly transonic to supersonic turbulence, while the filaments and clumps southwest of the B1 main core, which have no active young stars, have mostly subsonic turbulence. We have recently completed the observations of L1451, and results for that region will be revealed at the meeting. Released CLASSy data products can be found on our project website.Fil: Storm, Shaye. University of Maryland; Estados UnidosFil: Mundy, Lee G.. University of Maryland; Estados UnidosFil: Teuben, Peter J.. University of Maryland; Estados UnidosFil: Lee, Katherine. University of Maryland; Estados UnidosFil: Looney, Leslie. University of Illinois at Urbana; Estados UnidosFil: Fernandez Lopez, Manuel. Provincia de Buenos Aires. GobernaciĂłn. ComisiĂłn de Investigaciones CientĂficas. Instituto Argentino de RadioastronomĂa. Consejo Nacional de Investigaciones CientĂficas y TĂŠcnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto Argentino de RadioastronomĂa; ArgentinaFil: Rosolowsky, Erik. University of Alberta; CanadĂĄFil: Arce, Hector G.. University of Yale; Estados UnidosFil: Shirley, Yancy L.. University of Arizona; Estados UnidosFil: Segura Cox, Dominique. University of Illinois; Estados UnidosFil: Isella, Andrea. Caltech; Estados UnidosFil: CLASSy Collaboration. No especifĂca;223rd American Astronomical Society MeetingWashingtonEstados UnidosAmerican Astronomical Societ
Kinematics and Temperature Structures of Filaments in Serpens Main and Serpens South
We present a study of filaments in Serpens Main and Serpens South cluster regions based on N2H+(1-0) observations from the CARMA Large Area Star-formation Survey (CLASSy) and dust continuum images from the Herschel Space Observatory. Serpens Main and Serpens South are active star formation regions with prominent filamentary structures; however, the role of the filaments in the cluster formation is unclear. This study of filament structure and kinematics with high-angular resolution data (7 arcsecs), particularly in revealing possible infall signatures, provides physical insight to this question. Using the Herschel data, we estimate the temperature in and along filaments for comparison with their gas kinematics, spatial distribution, and N2H+(1-0) emission, to better understand their role in current star formation activities.Fil: Lee, Katherine. University of Maryland; Estados UnidosFil: Mundy, Lee G.. University of Maryland; Estados UnidosFil: Fernandez Lopez, Manuel. Provincia de Buenos Aires. GobernaciĂłn. ComisiĂłn de Investigaciones CientĂficas. Instituto Argentino de RadioastronomĂa. Consejo Nacional de Investigaciones CientĂficas y TĂŠcnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto Argentino de RadioastronomĂa; ArgentinaFil: Storm, Shaye. University of Maryland; Estados UnidosFil: Looney, Leslie. University of Illinois at Urbana- Champaign; Estados UnidosFil: Segura Cox, Dominique. University of Maryland; Estados UnidosFil: Teuben, Peter J.. University of Maryland; Estados UnidosFil: Rosolowsky, Erik. University of Alberta; CanadĂĄFil: Arce, Hector G.. Yale University; Estados UnidosFil: Shirley, Yancy L.. University of Arizona; Estados UnidosFil: Plunkett, Adele. Yale University; Estados UnidosFil: Isella, Andrea. Caltech; Estados UnidosFil: Tobin, John J.. National Radio Astronomy Observatory; Estados Unidos223th meeting of the American Astronomical SocietyWashingtonEstados UnidosAmerican Astronomical Societ
PanorĂĄmica del proyecto CLASSy: the CARMA Large Area Star Formation Survey
The CARMA Large Area Star-formation Survey (CLASSy) is a CARMA Key Project which is mapping 5 fields covering about 150 square-arcminutes each in the Perseus (3 fields) and Serpens (2 fields) Molecular Clouds. CLASSy consists of 3 mm interferometric observations with angular resolution, being sensitive to spatial scales between 1000 AU to 3 pc. Particularly, the analysis of the NH(1-0) molecular emission from the filamentary structures found in these star--forming regions constrain theoretical models explaining their origin and evolution. Gas kinematics observations show velocity gradients that suggest possible explanations on how filaments are formed. In addition, from the analysis of the kinematics we carried out a pioneer study of the turbulence in these clouds.Fil: Fernandez Lopez, Manuel. Provincia de Buenos Aires. GobernaciĂłn. ComisiĂłn de Investigaciones CientĂficas. Instituto Argentino de RadioastronomĂa. Consejo Nacional de Investigaciones CientĂficas y TĂŠcnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto Argentino de RadioastronomĂa; Argentina. University of Illinois at Urbana; Estados UnidosFil: Arce, H. G.. University of Yale; Estados UnidosFil: Looney, L. W.. University of Illinois at Urbana; Estados UnidosFil: Mundy, L. G.. University of Maryland; Estados UnidosFil: Storm, S.. University of Maryland; Estados UnidosFil: Lee, K.. University of Maryland; Estados UnidosFil: Teuben, P. J.. University of Maryland; Estados UnidosReuniĂłn de la AsociaciĂłn Argentina de AstronomĂaCĂłrdobaArgentinaInstituto de AstronomĂa TeĂłrica y Experimenta
Relating constructs of attention and working memory to social withdrawal in Alzheimer's disease and schizophrenia: issues regarding paradigm selection
Central nervous system diseases are not currently diagnosed based on knowledge of biological mechanisms underlying their symptoms. Greater understanding may be offered through an agnostic approach to traditional disease categories, where learning more about shared biological mechanisms across conditions could potentially reclassify sub-groups of patients to allow realisation of more effective treatments. This review represents the output of the collaborative group âPRISMâ, tasked with considering assay choices for assessment of attention and working memory in a transdiagnostic cohort of Alzheimer''s disease and schizophrenia patients exhibiting symptomatic spectra of social withdrawal. A multidimensional analysis of this nature has not been previously attempted. Nominated assays (continuous performance test III, attention network test, digit symbol substitution, N-back, complex span, spatial navigation in a virtual environment) reflected a necessary compromise between the need for broad assessment of the neuropsychological constructs in question with several pragmatic criteria: patient burden, compatibility with neurophysiologic measures and availability of preclinical homologues
Relating constructs of attention and working memory to social withdrawal in Alzheimer's disease and schizophrenia: issues regarding paradigm selection
Central nervous system diseases are not currently diagnosed based on knowledge of biological mechanisms underlying their symptoms. Greater understanding may be offered through an agnostic approach to traditional disease categories, where learning more about shared biological mechanisms across conditions could potentially reclassify sub-groups of patients to allow realisation of more effective treatments. This review represents the output of the collaborative group "PRISM", tasked with considering assay choices for assessment of attention and working memory in a transdiagnostic cohort of Alzheimer's disease and schizophrenia patients exhibiting symptomatic spectra of social withdrawal. A multidimensional analysis of this nature has not been previously attempted. Nominated assays (continuous performance test III, attention network test, digit symbol substitution, N-back, complex span, spatial navigation in a virtual environment) reflected a necessary compromise between the need for broad assessment of the neuropsychological constructs in question with several pragmatic criteria: patient burden, compatibility with neurophysiologic measures and availability of preclinical homologues
CARMA Large Area Star Formation Survey: Structure and Kinematics of Dense Gas in Serpens Main
We present observations of N2H+(1-0), HCO+(1-0), and HCN(1-0) toward the
Serpens Main molecular cloud from the CARMA Large Area Star Formation Survey
(CLASSy). We mapped 150 square arcminutes of Serpens Main with an angular
resolution of 7 arcsecs. The gas emission is concentrated in two subclusters
(the NW and SE subclusters). The SE subcluster has more prominent filamentary
structures and more complicated kinematics compared to the NW subcluster. The
majority of gas in the two subclusters has subsonic to sonic velocity
dispersions. We applied a dendrogram technique with N2H+(1-0) to study the gas
structures; the SE subcluster has a higher degree of hierarchy than the NW
subcluster. Combining the dendrogram and line fitting analyses reveals two
distinct relations: a flat relation between nonthermal velocity dispersion and
size, and a positive correlation between variation in velocity centroids and
size. The two relations imply a characteristic depth of 0.15 pc for the cloud.
Furthermore, we have identified six filaments in the SE subcluster. These
filaments have lengths of 0.2 pc and widths of 0.03 pc, which is smaller than a
characteristic width of 0.1 pc suggested by Herschel observations. The
filaments can be classified into two types based on their properties. The first
type, located in the northeast of the SE subcluster, has larger velocity
gradients, smaller masses, and nearly critical mass-per-unit-length ratios. The
other type, located in the southwest of the SE subcluster, has the opposite
properties. Several YSOs are formed along two filaments which have
supercritical mass per unit length ratios, while filaments with nearly critical
mass-per-unit-length ratios are not associated with YSOs, suggesting that stars
are formed on gravitationally unstable filaments.Comment: Accepted to ApJ. 38 pages, 16 figures, 5 table
Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at sqrt(s) = 7 TeV
The t t-bar production cross section (sigma[t t-bar]) is measured in
proton-proton collisions at sqrt(s) = 7 TeV in data collected by the CMS
experiment, corresponding to an integrated luminosity of 2.3 inverse
femtobarns. The measurement is performed in events with two leptons (electrons
or muons) in the final state, at least two jets identified as jets originating
from b quarks, and the presence of an imbalance in transverse momentum. The
measured value of sigma[t t-bar] for a top-quark mass of 172.5 GeV is 161.9 +/-
2.5 (stat.) +5.1/-5.0 (syst.) +/- 3.6(lumi.) pb, consistent with the prediction
of the standard model.Comment: Replaced with published version. Included journal reference and DO
Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV
A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay
channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7
TeV is presented. The data were collected at the LHC, with the CMS detector,
and correspond to an integrated luminosity of 4.6 inverse femtobarns. No
significant excess is observed above the background expectation, and upper
limits are set on the Higgs boson production cross section. The presence of the
standard model Higgs boson with a mass in the 270-440 GeV range is excluded at
95% confidence level.Comment: Submitted to JHE
Precise measurement of the W-boson mass with the CDF II detector
We have measured the W-boson mass MW using data corresponding to 2.2/fb of
integrated luminosity collected in proton-antiproton collisions at 1.96 TeV
with the CDF II detector at the Fermilab Tevatron collider. Samples consisting
of 470126 W->enu candidates and 624708 W->munu candidates yield the measurement
MW = 80387 +- 12 (stat) +- 15 (syst) = 80387 +- 19 MeV. This is the most
precise measurement of the W-boson mass to date and significantly exceeds the
precision of all previous measurements combined
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