Bayesian Model Comparison and Analysis of the Galactic Disk Population of Gamma-Ray Millisecond Pulsars

Pulsed emission from almost one hundred millisecond pulsars (MSPs) has been detected in $\gamma$-rays by the Fermi Large-Area Telescope. The global properties of this population remain relatively unconstrained despite many attempts to model their spatial and luminosity distributions. We perform here a self-consistent Bayesian analysis of both the spatial distribution and luminosity function simultaneously. Distance uncertainties, arising from errors in the parallax measurement or Galactic electron-density model, are marginalized over. We provide a public Python package for calculating distance uncertainties to pulsars derived using the dispersion measure by accounting for the uncertainties in Galactic electron-density model YMW16. Finally, we use multiple parameterizations for the MSP population and perform Bayesian model comparison, finding that a broken power law luminosity function with Lorimer spatial profile are preferred over multiple other parameterizations used in the past. The best-fit spatial distribution and number of $\gamma$-ray MSPs is consistent with results for the radio population of MSPs.Comment: 13 pages, 8 figures, 3 tables + Appendix. Public code and source list available from http://github.com/tedwards2412/MSPDis

Radio detection prospects for a bulge population of millisecond pulsars as suggested by Fermi LAT observations of the inner Galaxy

Analogously to globular clusters, the dense stellar environment of the Galactic center has been proposed to host a large population of as-yet undetected millisecond pulsars (MSPs). Recently, this hypothesis found support in the analysis of gamma rays from the inner Galaxy seen by the Large Area Telescope (LAT) aboard the Fermi satellite, which revealed a possible excess of diffuse GeV photons in the inner 15 deg about the Galactic center (Fermi GeV excess). The excess can be interpreted as the collective emission of thousands of MSPs in the Galactic bulge, with a spherical distribution that strongly peaks towards the Galactic center. In order to fully establish the MSP interpretation, it is essential to find corroborating evidence in multi-wavelength searches, most notably through the detection of radio pulsation from individual bulge MSPs. Based on globular cluster observations and the gamma-ray emission from the inner Galaxy, we investigate the prospects for detecting MSPs in the Galactic bulge. While previous pulsar surveys failed to identify this population, we demonstrate that, in the upcoming years, new large-area surveys with focus on regions a few degrees north or south of the Galactic center should lead to the detection of dozens of bulge MSPs. Additionally, we show that, in the near future, deep targeted searches of unassociated Fermi sources should be able to detect the first few MSPs in the bulge. The prospects for these deep searches are enhanced by a tentative gamma-ray/radio correlation that we infer from high-latitude gamma-ray MSPs. Such detections would constitute the first clear discoveries of field MSPs in the Galactic bulge, with far-reaching implications for gamma-ray observations, the formation history of the central Milky Way and strategy optimization for future radio observations.Comment: 24 pages, 17 figures, 5 tables. Minor clarifications. Matches version published in Ap

Spectral cutoffs in indirect dark matter searches

Indirect searches for dark matter annihilation or decay products in the cosmic-ray spectrum are plagued by the question of how to disentangle a dark matter signal from the omnipresent astrophysical background. One of the practically background-free smoking-gun signatures for dark matter would be the observation of a sharp cutoff or a pronounced bump in the gamma-ray energy spectrum. Such features are generically produced in many dark matter models by internal Bremsstrahlung, and they can be treated in a similar manner as the traditionally looked-for gamma-ray lines. Here, we discuss prospects for seeing such features with present and future Atmospheric Cherenkov Telescopes.Comment: 4 pages, 2 figures, 1 table; conference proceedings for TAUP 2011, Munich 5-9 Se

Disentangling Instrumental Features of the 130 GeV Fermi Line

We study the instrumental features of photons from the peak observed at $E_\gamma=130$ GeV in the spectrum of Fermi-LAT data. We use the {\sc sPlots} algorithm to reconstruct -- seperately for the photons in the peak and for background photons -- the distributions of incident angles, the recorded time, features of the spacecraft position, the zenith angles, the conversion type and details of the energy and direction reconstruction. The presence of a striking feature or cluster in such a variable would suggest an instrumental cause for the peak. In the publically available data, we find several suggestive features which may inform further studies by instrumental experts, though the size of the signal sample is too small to draw statistically significant conclusions.Comment: 9 pages, 22 figures; this version includes additional variables, study of stat sensitivity, and modification to the chi-sq calculatio

MIRU-VNTRplus: datenbankgestützte polyphasische Analyse von Mycobacterium tuberculosis complex Genotypisierungsdaten

Die molekulare Typisierung von Isolaten des Mycobacterium tuberculosis complex (MTBC) ist für viele epidemiologische Anwendungen von Bedeutung. Das Verfahren der Variable Number Tandem Repeats (VNTR) Typisierung wird hierzu immer wichtiger, da es sehr diskriminierend und sehr reproduzierbar ist. Bis jetzt gibt es noch keine Software zur Analyse von VNTR-Typisierungsdaten, die eine repräsentative und gut charakterisierte Referenzdatenbank beinhaltet. In die hier vorgestellte Datenbank wurden 187 Stämme der wichtigsten Lineages des MTBC aufgenommen. Für jeden dieser Stämme sind neben den Basisdaten auch VNTR-Daten für 24 Loki und vier weitere genetische Marker vorhanden. Benutzer können ihre Isolate auf zwei Arten mit der Referenzdatenbank vergleichen, durch Ähnlichkeitssuche oder durch Auswertung der Gruppierung in einem phylogenetischen Baum. Die für die Ähnlichkeitssuche notwendigen Schwellenwerte wurden durch eine Auswertung der Suchergebnisse für die Referenzstämme bestimmt

Representation of a complex Green function on a real basis: I. General Theory

When the Hamiltonian of a system is represented by a finite matrix, constructed from a discrete basis, the matrix representation of the resolvent covers only one branch. We show how all branches can be specified by the phase of a complex unit of time. This permits the Hamiltonian matrix to be constructed on a real basis; the only duty of the basis is to span the dynamical region of space, without regard for the particular asymptotic boundary conditions that pertain to the problem of interest.Comment: about 40 pages with 5 eps-figure

Mathematical Properties of a New Levin-Type Sequence Transformation Introduced by \v{C}\'{\i}\v{z}ek, Zamastil, and Sk\'{a}la. I. Algebraic Theory

\v{C}\'{\i}\v{z}ek, Zamastil, and Sk\'{a}la [J. Math. Phys. \textbf{44}, 962 - 968 (2003)] introduced in connection with the summation of the divergent perturbation expansion of the hydrogen atom in an external magnetic field a new sequence transformation which uses as input data not only the elements of a sequence $\{s_n \}_{n=0}^{\infty}$ of partial sums, but also explicit estimates $\{\omega_n \}_{n=0}^{\infty}$ for the truncation errors. The explicit incorporation of the information contained in the truncation error estimates makes this and related transformations potentially much more powerful than for instance Pad\'{e} approximants. Special cases of the new transformation are sequence transformations introduced by Levin [Int. J. Comput. Math. B \textbf{3}, 371 - 388 (1973)] and Weniger [Comput. Phys. Rep. \textbf{10}, 189 - 371 (1989), Sections 7 -9; Numer. Algor. \textbf{3}, 477 - 486 (1992)] and also a variant of Richardson extrapolation [Phil. Trans. Roy. Soc. London A \textbf{226}, 299 - 349 (1927)]. The algebraic theory of these transformations - explicit expressions, recurrence formulas, explicit expressions in the case of special remainder estimates, and asymptotic order estimates satisfied by rational approximants to power series - is formulated in terms of hitherto unknown mathematical properties of the new transformation introduced by \v{C}\'{\i}\v{z}ek, Zamastil, and Sk\'{a}la. This leads to a considerable formal simplification and unification.Comment: 41 + ii pages, LaTeX2e, 0 figures. Submitted to Journal of Mathematical Physic

Acceleration of generalized hypergeometric functions through precise remainder asymptotics

We express the asymptotics of the remainders of the partial sums {s_n} of the generalized hypergeometric function q+1_F_q through an inverse power series z^n n^l \sum_k c_k/n^k, where the exponent l and the asymptotic coefficients {c_k} may be recursively computed to any desired order from the hypergeometric parameters and argument. From this we derive a new series acceleration technique that can be applied to any such function, even with complex parameters and at the branch point z=1. For moderate parameters (up to approximately ten) a C implementation at fixed precision is very effective at computing these functions; for larger parameters an implementation in higher than machine precision would be needed. Even for larger parameters, however, our C implementation is able to correctly determine whether or not it has converged; and when it converges, its estimate of its error is accurate.Comment: 36 pages, 6 figures, LaTeX2e. Fixed sign error in Eq. (2.28), added several references, added comparison to other methods, and added discussion of recursion stabilit

Time resolved X ray absorption spectroscopy of infrared laser induced temperature jumps in liquid water

A time resolved X ray absorption study of the structural dynamics of liquid water on a picosecond timescale is presented. We apply femtosecond midinfrared pulses to resonantly excite the intramolecular O H stretching band of liquid water and monitor the transient response in the oxygen K edge absorption spectrum with picosecond X ray pulses. In this way, structural changes in the hydrogen bond network of liquid water upon an ultrafast temperature jump of approximately 20 K are investigated. The changes of the X ray absorption as induced by such a temperature jump are about 3.2 . This demonstrates that our method serves as a sensitive probe of transient structural changes in liquid water and that combined infrared laser synchrotron experiments with substantially shorter X ray pulses, such as generated with a femtosecond slicing scheme, are possibl

Assessing the severity of functional impairment of psychiatric disorders: equipercentile linking the mini-ICF-APP and CGI

BACKGROUND The assessment of functioning and impairment due to psychiatric illness has been acknowledged to be crucial for research and practice. This led to the development of the mini-ICF-APP, which provides a reliable and time-efficient measure of functioning and impairment. Although its use is increasing, it remains unclear how it reflects severity and how change might be interpreted from a clinical perspective. METHODS In a clinical sample of 3067 individuals hospitalized for mental health treatment, we used an equipercentile approach to link the mini-ICF-APP with the Clinical Global Impression scale (CGI) at admission and discharge. We linked the mini-ICF-APP sum score to the CGI-S scale and the mini-ICF-APP proportional change between admission and discharge to the CGI-I scale. RESULTS The mini-ICF-APP and CGI scales showed a Spearman correlation of 0.50 (p  .000); "no-change" in the CGI-I corresponded to an increase or decrease of 2%; "minimally-improved" to a mini-ICF-APP reduction of 3-30%; "much-improved" to a reduction of 31-63%; "very-much-improved" to a reduction of ≥64% "minimally-worse" to an increase of 3-34% "much-worse" to an increase of 35-67%; and finally "very-much-worse" with an increase of ≥68%. CONCLUSIONS Our findings improve understanding of the clinical meaning of the mini-ICF-APP sum score and percentage change in patients hospitalized for treatment