Stellar tracers of the Cygnus Arm. II: A young open cluster in Cam OB3

Cam OB3 is the only defined OB association believed to belong to the Outer Galactic Arm or Cygnus Arm. Very few members have been observed and the distance modulus to the association is not well known. We attempt a more complete description of the population of Cam OB3 and a better determination of its distance modulus. We present uvby photometry of the area surrounding the O-type stars BD +56 864 and LS I +57 138, finding a clear sequence of early-type stars that define an uncatalogued open cluster, which we call Alicante 1. We also present spectroscopy of stars in this cluster and the surrounding association. From the spectral types for 18 very likely members of the association and UBV photometry found in the literature, we derive individual reddenings, finding a extinction law close to standard and an average distance modulus DM=13.0+-0.4. This value is in excellent agreement with the distance modulus to the new cluster Alicante 1 found by fitting the photometric sequence to the ZAMS. In spite of the presence of several O-type stars, Alicante 1 is a very sparsely populated open cluster, with an almost total absence of early B-type stars. Our results definitely confirm Cam OB3 to be located on the Cygnus Arm and identify the first open cluster known to belong to the association.Comment: Accepted for publication in Astronomy & Astrophysics. Tables 7 & 8 to appear only in electronic forma

Learning a Factor Model via Regularized PCA

We consider the problem of learning a linear factor model. We propose a regularized form of principal component analysis (PCA) and demonstrate through experiments with synthetic and real data the superiority of resulting estimates to those produced by pre-existing factor analysis approaches. We also establish theoretical results that explain how our algorithm corrects the biases induced by conventional approaches. An important feature of our algorithm is that its computational requirements are similar to those of PCA, which enjoys wide use in large part due to its efficiency

Atomic Processes in Planetary Nebulae and H II Regions

Spectroscopic studies of Planetary Nebulae (PNe) and H {\sc ii} regions have driven much development in atomic physics. In the last few years the combination of a generation of powerful observatories, the development of ever more sophisticated spectral modeling codes, and large efforts on mass production of high quality atomic data have led to important progress in our understanding of the atomic spectra of such astronomical objects. In this paper I review such progress, including evaluations of atomic data by comparisons with nebular spectra, detection of spectral lines from most iron-peak elements and n-capture elements, observations of hyperfine emission lines and analysis of isotopic abundances, fluorescent processes, and new techniques for diagnosing physical conditions based on recombination spectra. The review is directed toward atomic physicists and spectroscopists trying to establish the current status of the atomic data and models and to know the main standing issues.Comment: 9 pages, 1 figur

Electron temperatures and densities of planetary nebulae determined from the nebular hydrogen recombination spectrum and temperature and density variations

A method is presented to derive electron temperatures and densities of planetary nebulae (PNe) simultaneously, using the observed hydrogen recombination spectrum, which includes continuum and line emission. By matching theoretical spectra to observed spectra around the Balmer jump at about 3646A, we determine electron temperatures and densities for 48 Galactic PNe. The electron temperatures based on this method are found to be systematically lower than those derived from [O III] 4959/4363 and [O III] (88\mu+52\mu)/4959 ratios. And the electron densities based on this method are found to be systematically higher than those derived from forbidden line ratios. These results suggest that temperature and density fluctuations are generally present within nebulae. In addition, He/H abundances of PNe are found to be positively correlated with the difference between T_e([O III]) and T_e(Bal), suggesting that He/H abundances might have been overestimated generally because of the possible existence of H-deficient knots.Comment: 41 pages, 10 figures, accepted for publication in MNRA

Paul Nizan: conspiracy and the contemplation of crime

Paul Nizan (1905-1940) is also known in France as the ‘impossible communist’, for his long-term allegiance to the Party and the abrupt cancellation of his membership, in the late 1930s, following the Nazi-Soviet pact. This paper discusses a number of his writings, focusing particularly on his best known novel, The Conspiracy, where a revolutionary cell plans illegal political action. Conflict, nihilism, suicide and betrayal are among the topics stemming from the novel, which will be examined from a criminological perspective. The analysis will primarily address ‘cultural’ aspects of crime and refer to notions such as ‘thrill’ and ‘seductions of crime’ among others. These notions, it will be argued, require some revision in the face of the imagined or actual criminality described in the novel

Sex wars and (trans) gender panics : identity and body politics in contemporary UK feminism

This article considers how sex and gender – as conceptual categories and as a lived experience – are subject to contestation and renegotiation in the contemporary UK. Exploring gendered shifts through the lenses of identity and embodiment, the article captures key moments where certainties have been undone within feminist and transgender thought and activism. Yet such fissures resound with calls for a return to traditional understandings of the sexed body. The article pays particular attention to debates within feminism around transgender issues, and sketches out a climate of transgender moral panic whereby conservative thinkers and some feminist activists are joining forces with the aim of resurrecting gender binaries

Measurements of elliptic and triangular flow in high-multiplicity 3^{3}He++Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV

We present the first measurement of elliptic ($v_2$) and triangular ($v_3$) flow in high-multiplicity $^{3}$He$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV. Two-particle correlations, where the particles have a large separation in pseudorapidity, are compared in $^{3}$He$+$Au and in $p$$+$$p$ collisions and indicate that collective effects dominate the second and third Fourier components for the correlations observed in the $^{3}$He$+$Au system. The collective behavior is quantified in terms of elliptic $v_2$ and triangular $v_3$ anisotropy coefficients measured with respect to their corresponding event planes. The $v_2$ values are comparable to those previously measured in $d$$+$Au collisions at the same nucleon-nucleon center-of-mass energy. Comparison with various theoretical predictions are made, including to models where the hot spots created by the impact of the three $^{3}$He nucleons on the Au nucleus expand hydrodynamically to generate the triangular flow. The agreement of these models with data may indicate the formation of low-viscosity quark-gluon plasma even in these small collision systems.Comment: 630 authors, 9 pages, 4 figures, 2 tables. v2 is the version accepted for publication by Physical Review Letters. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm