A New High Resolution CO Map of the inner 2.'5 of M51 I. Streaming Motions and Spiral Structure

[Abridged] The Owens Valley mm-Array has been used to map the CO 1--0 emission in the inner 2'.5 of the grand design spiral galaxy M51 at 2''-3'' resolution. The molecular spiral arms are revealed with unprecedented clarity: supermassive cloud complexes, Giant Molecular Associations, are for the first time resolved both along and perpendicular to the arms. Major complexes occur symmetrically opposite each other in the two major arms. Streaming motions can be studied in detail along the major and minor axes of M51. The streaming velocities are very large, 60-150 km/s. For the first time, sufficient resolution to resolve the structure in the molecular streaming motions is obtained. Our data support the presence of galactic shocks in the arms of M51. In general, velocity gradients across arms are higher by a factor of 2-10 than previously found. They vary in steepness along the spiral arms, becoming particularly steep in between GMAs. The steep gradients cause conditions of strong reverse shear in several regions in the arms, and thus the notion that shear is generally reduced by streaming motions in spiral arms will have to be modified. Of the three GMAs studied on the SW arm, only one shows reduced shear. We find an expansion in the NE molecular arm at 25'' radius SE of the center. This broadening occurs right after the end of the NE arm at the Inner Lindblad Resonance. Bifurcations in the molecular spiral arm structure, at a radius of 73'', may be evidence of a secondary compression of the gas caused by the 4/1 ultraharmonic resonance. Inside the radius of the ILR, we detect narrow (~ 5'') molecular spiral arms possibly related to the K-band arms found in the same region. We find evidence of non-circular motions in the inner 20'' which are consistent with gas on elliptical orbits in a bar.Comment: 29 pages, 15 figures, uses latex macros for ApJ; accepted for publication in Ap

Grid Loss: Detecting Occluded Faces

Detection of partially occluded objects is a challenging computer vision problem. Standard Convolutional Neural Network (CNN) detectors fail if parts of the detection window are occluded, since not every sub-part of the window is discriminative on its own. To address this issue, we propose a novel loss layer for CNNs, named grid loss, which minimizes the error rate on sub-blocks of a convolution layer independently rather than over the whole feature map. This results in parts being more discriminative on their own, enabling the detector to recover if the detection window is partially occluded. By mapping our loss layer back to a regular fully connected layer, no additional computational cost is incurred at runtime compared to standard CNNs. We demonstrate our method for face detection on several public face detection benchmarks and show that our method outperforms regular CNNs, is suitable for realtime applications and achieves state-of-the-art performance.Comment: accepted to ECCV 201

Spin order in the one-dimensional Kondo and Hund lattices

We study numerically the one-dimensional Kondo and Hund lattices consisting of localized spins interacting antiferro or ferromagnetically with the itinerant electrons, respectively. Using the Density Matrix Renormalization Group we find, for both models and in the small coupling regime, the existence of new magnetic phases where the local spins order forming ferromagnetic islands coupled antiferromagnetically. Furthermore, by increasing the interaction parameter $|J|$ we find that this order evolves toward the ferromagnetic regime through a spiral-like phase with longer characteristic wave lengths. These results shed new light on the zero temperature magnetic phase diagram for these models.Comment: PRL, to appea

Vlasov scaling for the Glauber dynamics in continuum

We consider Vlasov-type scaling for the Glauber dynamics in continuum with a positive integrable potential, and construct rescaled and limiting evolutions of correlation functions. Convergence to the limiting evolution for the positive density system in infinite volume is shown. Chaos preservation property of this evolution gives a possibility to derive a non-linear Vlasov-type equation for the particle density of the limiting system.Comment: 32 page

Simulating spin-3/2 particles at colliders

Support for interactions of spin-3/2 particles is implemented in the FeynRules and ALOHA packages and tested with the MadGraph 5 and CalcHEP event generators in the context of three phenomenological applications. In the first, we implement a spin-3/2 Majorana gravitino field, as in local supersymmetric models, and study gravitino and gluino pair-production. In the second, a spin-3/2 Dirac top-quark excitation, inspired from compositness models, is implemented. We then investigate both top-quark excitation and top-quark pair-production. In the third, a general effective operator for a spin-3/2 Dirac quark excitation is implemented, followed by a calculation of the angular distribution of the s-channel production mechanism.Comment: 20 pages, 7 figure