اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدThe Gerstenhaber product $HH^2(A)times HH^2(A)to HH^3(A)$ of affine toric varieties
119
0
0.0
(
0
)
تأليف
Matej Filip
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
For an affine toric variety $spec(A)$, we give a convex geometric interpretation of the Gerstenhaber product $HH^2(A)times HH^2(A)to HH^3(A)$ between the Hochschild cohomology groups. In the case of Gorenstein toric surfaces we prove that the Gerstenhaber product is the zero map. As an application in commutative deformation theory we find the equations of the versal base space (in special lattice degrees) up to second order for not necessarily isolated toric Gorenstein singularities. Our construction reproves and generalizes results obtained in [1] and [13].
قيم البحث
اقرأ أيضاً
HH 175 is an isolated Herbig-Haro object seen towards the B35 cloud in the lambda Ori region. We use deep Subaru 8m interference filter images and Spitzer images to show that HH 175 is a terminal shock in a large collimated outflow from the nearby em
bedded source IRAS 05417+0907. The body of the eastern outflow lobe is hidden by a dense ridge of gas. The western outflow breaks out of the front of the cometary-shaped B35 cloud, carrying cloud fragments along, which are optically visible due to photoionization by the massive lambda Ori stars. The total extent of the bipolar outflow is 13.7 arcmin, which at the adopted distance of 415 pc corresponds to a projected dimension of 1.65 pc. The embedded source IRAS 05417+0907 is located on the flow axis approximately midway between the two lobes, and near-infrared images show it to be a multiple system of 6 sources, with a total luminosity of 31 Lsun. Millimeter maps in CO, 13CO, and C18O show that the B35 cloud is highly structured with multiple cores, of which the one that spawned IRAS 05417+0907 is located at the apex of B35. It is likely that the embedded source is the result of compression by an ionization-shock front driven by the lambda Ori OB stars.
We present optical linear polarimetry in the line of sight to HH135/HH136. The polarimetry of the field stars reveals two populations: one corresponds to a foreground interstellar component; the other originates in the interstellar medium in the vici
nity of the Herbig-Haro pair and, therefore, can be used to study the magnetic field in the star forming region. Its direction is aligned with the jet of HH135/HH136, which could be an indication that the interstellar magnetic field is important in the outflow collimation. The interstellar magnetic field magnitude was estimated to be of order 90 uG. According to recent numerical simulations, an interstellar magnetic field of such strength can be important in the definition of the outflow direction. There is also evidence that the associated dark cloud has an elongation parallel to the magnetic field. Our image polarimetry of the extended emission associated with HH135/HH136 shows a centro-symmetric pattern pointing to the knot E of HH136. Previous near infrared polarimetry traces a different illumination center, namely IRAS 11101-5829 - the probable exciting source of the system. This discrepancy can be explained if the YSO emission is completely blocked in optical wavelengths and the dominant optical source in the region is the knot E, whose nature is uncertain. A discussion of the spectral energy distributions of HH136-E and IRAS 11101-5829 is presented.
We present a comparison between the time-evolution over the past $sim 20$ years of the radio continuum and H$alpha$ emission of HH~1 and 2. We find that the radio continuum and the H$alpha$ emission of both objects show very similar trends, with HH~1
becoming fainter and HH~2 brightening quite considerably (about a factor of 2). We also find that the $F_{rm Halpha}/F_{ff}$ (H$alpha$ to free-free continuum) ratio of HH~1 and 2 has higher values than the ones typically found in planetary nebulae (PNe) which we interpret as an indication that the H$alpha$ and free-free emission of HH~1/2 is produced in emitting regions with lower temperatures ($sim 2000$~K) than the emission of PNe (with $sim 10^4$~K).
We present new results on the kinematics of the jet HH 110. New proper motion measurements have been calculated from [SII] CCD images obtained with a time baseline of nearly fifteen years. HH 110 proper motions show a strong asymmetry with respect to
the outflow axis, with a general trend of pointing towards the west of the axis direction. Spatial velocities have been obtained by combining the proper motions and radial velocities from Fabry-Perot data. Velocities decrease by a factor ~3 over a distance of ~10$^{18}$ cm, much shorter than the distances expected for the braking caused by the jet/environment interaction. Our results show evidence of an anomalously strong interaction between the outflow and the surrounding environment, and are compatible with the scenario in which HH 110 emerges from a deflection in a jet/cloud collision.
We present high angular resolution, high sensitivity 8.46 GHz (3.6 cm) radio continuum observations made toward the core of the HH~92 outflow with the Very Large Array in 2002-2003 and with the Expanded Very Large Array in 2011. We detect a group of
three compact sources distributed in a region 2$$ in extension and discuss their nature. We conclude that one of the objects (VLA 1) is the exciting source of the giant outflow associated with HH~92. In the case of HH~34 we present new 43.3 GHz (7 mm) observations that reveal the presence of a structure associated with the exciting source and elongated perpendicular to the highly collimated optical jet in the region. We propose that this 7 mm source is a circumstellar disk with radius of $sim$80 AU and mass of $sim$0.21 $M_odot$.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
