Star formation, structure, and formation mechanism of cometary globules: NIR observations of CG 1 and CG 2

Cometary globule (CG) 1 and CG 2 are "classic" CGs in the Gum Nebula. They have compact heads and long dusty tails that point away from the centre of the Gum Nebula. We study the structure of CG 1 and CG 2 and the star formation in them to find clues to the CG formation mechanism. The two possible mechanisms, radiation-driven implosion (RDI) and a supernova (SN) blast wave, produce a characteristic mass distribution where the major part of the mass is situated in either the head (RDI) or the tail (SN). CG 1 and CG 2 were imaged in the near infrared (NIR) JsHKs bands. NIR photometry was used to locate NIR excess objects and to create extinction maps of the CGs. The A_V maps allow us to analyse the large-scale structure of CG 1 and CG 2. Archival images from the WISE and Spitzer satellites and HIRES-processed IRAS images were used to study the small-scale structure. In addition to the previously known CG 1 IRS 1 we discovered three new NIR-excess objects, two in CG 1 and one in CG 2. CG 2 IRS 1 is the first detection of star formation in CG 2. Spectral energy distribution (SED) fitting suggests the NIR-excess objects are young low-mass stars. CG 1 IRS 1 is probably a class I protostar in the head of CG 1. CG 1 IRS 1 drives a bipolar outflow, which is very weak in CO, but the cavity walls are seen in reflected light in our NIR and in the Spitzer 3.6 and 4.5 mum images. Strong emission from excited polycyclic aromatic hydrocarbon particles and very small grains were detected in the CG 1 tail. The total mass of CG 1 in the observed area is 41.9 Msun of which 16.8 Msun lies in the head. For CG 2 these values are 31.0 Msun total and 19.1 Msun in the head. The observed mass distribution does not offer a firm conclusion for the formation mechanism of these CGs: CG 1 is in too evolved a state, and in CG 2 part of the globule tail was outside the observed area. (abridged)Comment: Accepted for publication in A&A. 22 pages, 24 figures. JHKs photometry will be available electronicall

Rosette Globulettes and Shells in the Infrared

Tiny, dense clumps of sub-solar mass called globulettes form in giant galactic HII regions. The young central clusters compress the surrounding molecular shells which break up into clumps, filaments, and elephant trunks that interact with UV light from the central OB stars. We study the nature of the infrared emission and extinction in the shell and globulettes in the Rosette Nebula (RN) and search for associated newborn stars. We imaged the northwestern quadrant of the RN in the near-infrared (NIR) through JHKs and narrow-band H2 1-0 S(1), Pbeta and continuum filters. NIR images were used to study the surface brightness of the globulettes and associated bright rims. NIR photometry was used to create an extinction map and to search for NIR excess objects. Archival images from Spitzer IRAC and MIPS 24 and Herschel PACS observations were used to further study the region and its stellar population and to examine the structure of the shell and trunks. The globulettes and elephant trunks have bright rims in the Ks band on the sides facing the central cluster. Analysis of 21 globulettes where surface brightness in the H2 1-0 S(1) line is detected shows that about a third of the surface brightness observed in Ks is due to this line: the observed average of the H2/Ks surface brightness is 0.26+-0.02 in the globulettes cores and 0.30+-0.01 in the rims. The estimated H2 1-0 S(1) surface brightness of the rims is 3-8*10^{-8} Wm^{-2}sr^{-1}um^{-1}. The H2/Ks surface brightness ratio supports fluorescence as the H2 excitation mechanism. The globulettes have number densities of n(H2)~10^{-4} cm^{-3} or higher. We confirm the results from previous optical and CO surveys that the larger globulettes contain very dense cores and dense envelopes, and that their masses are sub-solar. Two NIR protostellar objects were found in an elephant trunk and one in the most massive globulette in our study. (abridged)Comment: Accepted for publication in A&A. 24 pages, 27 figures. JHKs photometry will be available electronicall

Rosette nebula globules: Seahorse giving birth to a star

The Rosette Nebula is an HII region ionized mainly by the stellar cluster NGC 2244. Elephant trunks, globules, and globulettes are seen at the interface where the HII region and the surrounding molecular shell meet. We have observed a field in the northwestern part of the Rosette Nebula where we study the small globules protruding from the shell. Our aim is to measure their properties and study their star formation history in continuation of our earlier study of the features of the region. We imaged the region in broadband near-infrared (NIR) JsHKs filters and narrowband H2 1-0 S(1), P$\beta$, and continuum filters using the SOFI camera at the ESO/NTT. The imaging was used to study the stellar population and surface brightness, create visual extinction maps, and locate star formation. Mid-infrared (MIR) Spitzer IRAC and WISE and optical NOT images were used to further study the star formation and the structure of the globules. The NIR and MIR observations indicate an outflow, which is confirmed with CO observations made with APEX. The globules have mean number densities of ~$4.6\times10^4 \rm cm^{-3}$. P$\beta$ is seen in absorption in the cores of the globules where we measure visual extinctions of 11-16 mag. The shell and the globules have bright rims in the observed bands. In the Ks band 20 to 40% of the emission is due to fluorescent emission in the 2.12 $\mu$m H2 line similar to the tiny dense globulettes we studied earlier in a nearby region. We identify several stellar NIR excess candidates and four of them are also detected in the Spitzer IRAC 8.0 $\mu$m image and studied further. We find an outflow with a cavity wall bright in the 2.124 $\mu$m H2 line and at 8.0 $\mu$m in one of the globules. The outflow originates from a Class I young stellar object (YSO) embedded deep inside the globule. An H$\alpha$ image suggests the YSO drives a possible parsec-scale outflow. (abridged)Comment: 20 pages, 19 figures, accepted for publication in Astronomy and Astrophysics, figures reduced for astro-p

Inert states of spin-S systems

We present a simple but efficient geometrical method for determining the inert states of spin-S systems. It can be used if the system is described by a spin vector of a spin-S particle and its energy is invariant in spin rotations and phase changes. Our method is applicable to an arbitrary S and it is based on the representation of a pure spin state of a spin-S particle in terms of 2S points on the surface of a sphere. We use this method to find candidates for some of the ground states of spinor Bose-Einstein condensates.Comment: 4 pages, 2 figures, minor changes, references added, typos correcte

Radiation of the Inner Horizon of the Reissner-Nordstr\"om Black Hole

Despite of over thirty years of research of the black hole thermodynamics our understanding of the possible role played by the inner horizons of Reissner-Nordstr\"om and Kerr-Newman black holes in black hole thermodynamics is still somewhat incomplete: There are derivations which imply that the temperature of the inner horizon is negative and it is not quite clear what this means. Motivated by this problem we perform a detailed analysis of the radiation emitted by the inner horizon of the Reissner-Nordstr\"om black hole. As a result we find that in a maximally extended Reissner-Nordstr\"om spacetime virtual particle-antiparticle pairs are created at the inner horizon of the Reissner-Nordstr\"om black hole such that real particles with positive energy and temperature are emitted towards the singularity from the inner horizon and, as a consequence, antiparticles with negative energy are radiated away from the singularity through the inner horizon. We show that these antiparticles will come out from the white hole horizon in the maximally extended Reissner-Nordstr\"om spacetime, at least when the hole is near extremality. The energy spectrum of the antiparticles leads to a positive temperature for the white hole horizon. In other words, our analysis predicts that in addition to the radiation effects of black hole horizons, also the white hole horizon radiates. The black hole radiation is caused by the quantum effects at the outer horizon, whereas the white hole radiation is caused by the quantum effects at the inner horizon of the Reissner-Nordstr\"om black hole.Comment: 22 pages, 6 figures. References added, discussion slightly expanded in Secs. I and V. To appear in IJMP

Floquet analysis of the modulated two-mode Bose-Hubbard model

We study the tunneling dynamics in a time-periodically modulated two-mode Bose-Hubbard model using Floquet theory. We consider situations where the system is in the self-trapping regime and either the tunneling amplitude, the interaction strength, or the energy difference between the modes is modulated. In the former two cases, the tunneling is enhanced in a wide range of modulation frequencies, while in the latter case the resonance is narrow. We explain this difference with the help of Floquet analysis. If the modulation amplitude is weak, the locations of the resonances can be found using the spectrum of the non-modulated Hamiltonian. Furthermore, we use Floquet analysis to explain the coherent destruction of tunneling (CDT) occurring in a large-amplitude modulated system. Finally, we present two ways to create a NOON state (a superposition of $N$ particles in mode 1 with zero particles in mode 2 and vice versa). One is based on a coherent oscillation caused by detuning from a partial CDT. The other makes use of an adiabatic variation of the modulation frequency. This results in a Landau-Zener type of transition between the ground state and a NOON-like state.Comment: 16 pages, 11 figures; published in Phys. Rev.

Explicit expressions for the topological defects of spinor Bose-Einstein condensates

In this paper we first derive a general method which enables one to create expressions for vortices and monopoles. By using this method we construct several order-parameters describing the vortices and monopoles of Bose-Einstein condensates with hyperfine spin F=1 and F=2. We concentrate on defects which are topologically stable in the absence of an external magnetic field. In particular we show that in a ferromagnetic condensate there can be a vortex which does not produce any superfluid flow. We also point out that the order-parameter space of the cyclic phase of F=2 condensate consists of two disconnected sets. Finally we examine the effect of an external magnetic field on the vortices of a ferromagnetic F=1 condensate and discuss the experimental preparation of a vortex in this system.Comment: 17 pages, partly rewritten to improve clarity, conclusions unchange

Interplanetary shocks lacking type II radio bursts

We report on the radio-emission characteristics of 222 interplanetary (IP) shocks. A surprisingly large fraction of the IP shocks (~34%) is radio quiet (i.e., the shocks lacked type II radio bursts). The CMEs associated with the RQ shocks are generally slow (average speed ~535 km/s) and only ~40% of the CMEs were halos. The corresponding numbers for CMEs associated with radio loud (RL) shocks are 1237 km/s and 72%, respectively. The RQ shocks are also accompanied by lower peak soft X-ray flux. CMEs associated with RQ (RL) shocks are generally accelerating (decelerating). The kinematics of CMEs associated with the km type II bursts is similar to those of RQ shocks, except that the former are slightly more energetic. Comparison of the shock The RQ shocks seem to be mostly subcritical and quasi-perpendicular. The radio-quietness is predominant in the rise phase and decreases through the maximum and declining phases of solar cycle 23. The solar sources of the shock-driving CMEs follow the sunspot butterfly diagram, consistent with the higher-energy requirement for driving shocks

Monitoring asthma in childhood : symptoms, exacerbations and quality of life

Acknowledgements The Task Force members and their affiliations are as follows. Paul L.P. Brand: Princess Amalia Children’s Centre, Isala Hospital, Zwolle, and UMCG Postgraduate School of Medicine, University Medical Centre and University of Groningen, Groningen, The Netherlands; Mika J. Mäkelä: Skin and Allergy Hospital, Helsinki University Hospital, Helsinki, Finland; Stanley J. Szefler: Children’s Hospital Colorado and University of Colorado Denver School of Medicine, Denver, CO, USA; Thomas Frischer: Dept of Paediatrics and Paediatric Surgery, Wilhelminenspital, Vienna, Austria; David Price: Dept of Primary Care Respiratory Medicine, Academic Primary Care, Division of Applied Health Sciences, University of Aberdeen, Aberdeen, UK; Eugenio Baraldi: Women’s and Children’s Health Dept, Unit of Respiratory Medicine and Allergy, University of Padova, Padova, Italy; Kai-Hakon Carlsen: Dept of Paediatrics, Women and Children’s Division, University of Oslo, and Oslo University Hospital, Oslo, Norway; Ernst Eber: Respiratory and Allergic Disease Division, Dept of Paediatrics and Adolescence Medicine, Medical University of Graz, Graz, Austria; Gunilla Hedlin: Dept of Women’s and Children’s Health and Centre for Allergy Research, Karolinska Institutet, and Astrid Lindgren Children’s hospital, Stockholm, Sweden; Neeta Kulkarni: Leicestershire Partnership Trust and Dept of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK; Christiane Lex: Dept of Paediatric Cardiology and Intensive Care Medicine, Division of Paediatric Respiratory Medicine, University Hospital Goettingen, Goettingen, Germany; Karin C. Lødrup Carlsen: Dept of Paediatrics, Women and Children’s Division, Oslo University Hospital, and Dept of Paediatrics, Faculty of Medicine, University of Oslo, Oslo, Norway; Eva Mantzouranis: Dept of Paediatrics, University Hospital of Heraklion, University of Crete, Heraklion, Greece; Alexander Moeller: Division of Respiratory Medicine, University Children’s Hospital Zurich, Zurich, Switzerland; Ian Pavord: Dept of Respiratory Medicine, University of Oxford, Oxford, UK; Giorgio Piacentini: Paediatric Section, Dept of Life and Reproduction Sciences, University of Verona, Verona, Italy; Mariëlle W. Pijnenburg: Dept Paediatrics/Paediatric Respiratory Medicine, Erasmus MC - Sophia Children’s Hospital, Rotterdam, The Netherlands; Bart L. Rottier: Dept of Pediatric Pulmonology and Allergology, GRIAC Research Institute, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; Sejal Saglani: Leukocyte Biology and Respiratory Paediatrics, National Heart and Lung Institute, Imperial College London, London, UK; Peter D. Sly: Queensland Children’s Medical Research Institute, The University of Queensland, Brisbane, Australia; Steve Turner: Dept of Paediatrics, University of Aberdeen, Aberdeen, UK; Edwina Wooler: Royal Alexandra Children’s Hospital, Brighton, UK.Peer reviewedPublisher PD