L-band ATS 5/Orion/S. S. Manhattan marine navigation and communication experiment Final report

L-band signals relayed by synchronous satellite for navigation and data communicatio

Search for grain growth towards the center of L1544

In dense and cold molecular clouds dust grains are surrounded by thick icy mantles. It is however not clear if dust growth and coagulation take place before the switch-on of a protostar. This is an important issue, as the presence of large grains may affect the chemical structure of dense cloud cores, including the dynamically important ionization fraction, and the future evolution of solids in protoplanetary disks. To study this further, we focus on L1544, one of the most centrally concentrated pre-stellar cores on the verge of star formation, and with a well-known physical structure. We observed L1544 at 1.2 and 2 mm using NIKA, a new receiver at the IRAM 30 m telescope, and we used data from the Herschel Space Observatory archive. We find no evidence of grain growth towards the center of L1544 at the available angular resolution. Therefore, we conclude that single dish observations do not allow us to investigate grain growth toward the pre-stellar core L1544 and high sensitivity interferometer observations are needed. We predict that dust grains can grow to 200 $\mu$m in size toward the central ~300 au of L1544. This will imply a dust opacity change by a factor of ~2.5 at 1.2 mm, which can be detected using the Atacama Large Millimeter and submillimeter Array (ALMA) at different wavelengths and with an angular resolution of 2".Comment: 12 pages, 14 figures. Accepted for publication in A&

Search for Interstellar Water in the Translucent Molecular Cloud toward HD 154368

We report an upper limit of 9 x 10^{12} cm-2 on the column density of water in the translucent cloud along the line of sight toward HD 154368. This result is based upon a search for the C-X band of water near 1240 \AA carried out using the Goddard High Resolution Spectrograph of the Hubble Space Telescope. Our observational limit on the water abundance together with detailed chemical models of translucent clouds and previous measurements of OH along the line of sight constrain the branching ratio in the dissociative recombination of H_3O+ to form water. We find at the $3\sigma$ level that no more than 30% of dissociative recombinations of H_3O+ can lead to H_2O. The observed spectrum also yielded high-resolution observations of the Mg II doublet at 1239.9 \AA and 1240.4 \AA, allowing the velocity structure of the dominant ionization state of magnesium to be studied along the line of sight. The Mg II spectrum is consistent with GHRS observations at lower spectral resolution that were obtained previously but allow an additional velocity component to be identified.Comment: Accepted by ApJ, uses aasp

Models for Dusty Lyman alpha Emitters at High Redshift

Models are presented for the Lyman alpha emission of dusty high-redshift galaxies by combining the Press-Schechter formalism with a treatment of the inhomogeneous dust distribution inside galaxies. It is found that the amount of Lyman alpha radiation escaping from the galaxies strongly depends on the time over which the dust is produced through stellar activity, and on the ambient inhomogeneity of the HII regions that surround the ionizing OB stars. Good agreement is found with recent observations, as well as previous non-detections. Our models indicate that the dust content builds up in no more than approximately 5x10^8 yr, the galactic HII regions are inhomogeneous with a cloud covering factor of order unity, and the overall star formation efficiency is at least about 5%. It is predicted that future observations can detect these Lyman alpha galaxies upto redshifts of about 8.Comment: 16 pages, 4 figures, submitted to Ap

Far-Infrared and Sub-Millimeter Observations and Physical Models of the Reflection Nebula Ced 201

ISO [C II] 158 micron, [O I] 63 micron, and H_2 9 and 17 micron observations are presented of the reflection nebula Ced 201, which is a photon-dominated region illuminated by a B9.5 star with a color temperature of 10,000 K (a cool PDR). In combination with ground based [C I] 609 micron, CO, 13CO, CS and HCO+ data, the carbon budget and physical structure of the reflection nebula are constrained. The obtained data set is the first one to contain all important cooling lines of a cool PDR, and allows a comparison to be made with classical PDRs. To this effect one- and three-dimensional PDR models are presented which incorporate the physical characteristics of the source, and are aimed at understanding the dominant heating processes of the cloud. The contribution of very small grains to the photo-electric heating rate is estimated from these models and used to constrain the total abundance of PAHs and small grains. Observations of the pure rotational H_2 lines with ISO, in particular the S(3) line, indicate the presence of a small amount of very warm, approximately 330 K, molecular gas. This gas cannot be accommodated by the presented models

Healthcare reimbursement costs of children with type 1 diabetes in the Netherlands, a observational nationwide study (Young Dudes-4)

Background: Type 1 diabetes mellitus (T1DM) is one of the most common chronic diseases in children. Studies on costs related to T1DM are scarce and focused primarily on the costs directly related to diabetes. We aimed to investigate both the overall healthcare costs and the more specific costs related to the management of diabetes.Methods: This is a retrospective and observational, nationwide cohort study of all Dutch children (aged 0-18 years) with T1DM. Data were collected from the national registry for healthcare reimbursement, in which all Dutch insurance companies combine their reimbursement data. In the Netherlands for all Dutch citizens health care is covered by law and all children are treated by hospital-based paediatricians.Results: We analysed 6710 children distributed over 81 hospitals: 475 children in 6 university hospitals and 6235 children in 75 general hospitals. Total reimbursement for all children with T1DM over the period 2009 to 2011 was (sic) 167,494,732 corresponding to an annual mean of (sic) 55,831,577 of total costs and (sic) 8326 euros per child. When comparing small (between 26 and 54 patients), medium (57-84 patients) and large (88-248 patients) general hospitals, costs per patient were highest in the hospitals with the highest number of T1DM patients. The costs for devices, secondary care and pharmaceutics had most impact on total expenditures. Over the study period, there was a slight decrease in per person costs.Conclusion: The overall health expenditure of a child with T1DM is more than (sic) 8000 per patient per annum. Given the move towards more device-intensive multidisciplinary care for these patients, the costs of treating T1DM in children are likely to increase further in the coming years.</p

Molecular line emission in NGC1068 imaged with ALMA: II. The chemistry of the dense molecular gas

We present a detailed analysis of ALMA Bands 7 and 9 data of CO, HCO+, HCN and CS, augmented with Plateau de Bure Interferometer (PdBI) data of the ~ 200 pc circumnuclear disk (CND) and the ~ 1.3 kpc starburst ring (SB ring) of NGC~1068, a nearby (D = 14 Mpc) Seyfert 2 barred galaxy. We aim at determining the physical characteristics of the dense gas present in the CND and whether the different line intensity ratios we find within the CND as well as between the CND and the SB ring are due to excitation effects (gas density and temperature differences) or to a different chemistry. We estimate the column densities of each species in Local Thermodynamic Equilibrium (LTE). We then compute large one-dimensional non-LTE radiative transfer grids (using RADEX) by using first only the CO transitions, and then all the available molecules in order to constrain the densities, temperatures and column densities within the CND. We finally present a preliminary set of chemical models to determine the origin of the gas. We find that in general the gas in the CND is very dense (> 10^5 cm^-3) and hot (T> 150K), with differences especially in the temperature across the CND. The AGN position has the lowest CO/HCO+, CO/HCN and CO/CS column density ratios. RADEX analyses seem to indicate that there is chemical differentiation across the CND. We also find differences between the chemistry of the SB ring and some regions of the CND; the SB ring is also much colder and less dense than the CND. Chemical modelling does not succeed in reproducing all the molecular ratios with one model per region, suggesting the presence of multi-gas phase components. The LTE, RADEX and chemical analyses all indicate that more than one gas-phase component is necessary to uniquely fit all the available molecular ratios within the CND.Comment: Accepted by A&A; please contact the author for a better version of the pdf where the resolution and positions of figures are as they will appear in the Journa

Numerical simulations of expanding supershells in dwarf irregular galaxies. I. Application to Holmberg I

Numerical hydrodynamical modelling of supernova-driven shell formation is performed with a purpose to reproduce a giant HI ring (diameter 1.7 kpc) in the dwarf irregular galaxy Holmberg I (Ho I). We find that the contrast in HI surface density between the central HI depression and the ring is sensitive to the shape of the gravitational potential. This circumstance can be used to constrain the total mass (including the dark matter halo) of nearly face-on dwarf irregulars. We consider two models of Ho I, which differ by an assumed mass of the dark matter halo M_h. The contrast in HI surface density between the central HI depression and the ring, as well as the lack of gas expansion in the central hole, are better reproduced by the model with a massive halo of M_h=6.0*10^9 M_sun than by that with a small halo of M_h=4.0*10^8 M_sun, implying that Ho I is halo-dominated. Assuming the halo mass of 6.0*10^9 M_sum, we determine the mechanical energy required to form the observed ring equal to (3.0 +- 0.5)*10^53 ergs, equivalent 300+-50 Type II supernovae. The inclination of Ho I is constrained to 15-20 degrees by comparing the modelled HI spectrum and channel maps with those observed.Comment: 11 pages, 11 figures, accepted for publication in Astronomy and Astrophysic

Probing highly obscured, self-absorbed galaxy nuclei with vibrationally excited HCN

We present high resolution (0."4) IRAM PdBI and ALMA mm and submm observations of the (ultra) luminous infrared galaxies ((U)LIRGs) IRAS17208-0014, Arp220, IC860 and Zw049.057 that reveal intense line emission from vibrationally excited ($\nu_2$=1) J=3-2 and 4-3 HCN. The emission is emerging from buried, compact (r<17-70 pc) nuclei that have very high implied mid-infrared surface brightness $>$$5\times 10^{13}$ L$_{\odot}$ kpc$^{-2}$. These nuclei are likely powered by accreting supermassive black holes (SMBHs) and/or hot (>200 K) extreme starbursts. Vibrational, $\nu_2$=1, lines of HCN are excited by intense 14 micron mid-infrared emission and are excellent probes of the dynamics, masses, and physical conditions of (U)LIRG nuclei when H$_2$ column densities exceed $10^{24}$ cm$^{-2}$. It is clear that these lines open up a new interesting avenue to gain access to the most obscured AGNs and starbursts. Vibrationally excited HCN acts as a proxy for the absorbed mid-infrared emission from the embedded nuclei, which allows for reconstruction of the intrinsic, hotter dust SED. In contrast, we show strong evidence that the ground vibrational state ($\nu$=0), J=3-2 and 4-3 rotational lines of HCN and HCO$^+$ fail to probe the highly enshrouded, compact nuclear regions owing to strong self- and continuum absorption. The HCN and HCO$^+$ line profiles are double-peaked because of the absorption and show evidence of non-circular motions - possibly in the form of in- or outflows. Detections of vibrationally excited HCN in external galaxies are so far limited to ULIRGs and early-type spiral LIRGs, and we discuss possible causes for this. We tentatively suggest that the peak of vibrationally excited HCN emission is connected to a rapid stage of nuclear growth, before the phase of strong feedback.Comment: 13 pages, 7 figures, accepted for publication in Astronomy and Astrophysic

Herschel-PACS Observations of Far-IR CO Line Emission in NGC 1068: Highly Excited Molecular Gas in the Circumnuclear Disk

We report the detection of far-IR CO rotational emission from the prototypical Seyfert 2 galaxy NGC 1068. Using Herschel-PACS, we have detected 11 transitions in the J_upper=14-30 (E_upper/k_B = 580-2565 K) range, all of which are consistent with arising from within the central 10" (700 pc). The detected transitions are modeled as arising from 2 different components: a moderate excitation (ME) component close to the galaxy systemic velocity, and a high excitation (HE) component that is blueshifted by ~80 km s^{-1}. We employ a large velocity gradient (LVG) model and derive n_H2~10^{5.6} cm^{-3}, T_kin~170 K, and M_H2~10^{6.7} M_sun for the ME component, and n_H2~10^{6.4} cm^{-3}, T_kin~570 K, and M_H2~10^{5.6} M_sun for the HE component, although for both components the uncertainties in the density and mass are plus/minus (0.6-0.9) dex. We compare the CO line profiles with those of other molecular tracers observed at higher spatial and spectral resolution, and find that the ME transitions are consistent with these lines arising in the ~200 pc diameter ring of material traced by H_2 1-0 S(1) observations. The blueshift of the HE lines may also be consistent with the bluest regions of this H_2 ring, but a better kinematic match is found with a clump of infalling gas ~40 pc north of the AGN. We discuss the prospects of placing the HE component near the AGN, and conclude that while the moderate thermal pressure precludes an association with the ~1 pc radius H_2O maser disk, the HE component could potentially be located only a few parsecs more distant from the AGN, and might then provide the N_H~10^{25} cm^{-2} column obscuring the nuclear hard X-rays. Finally, we also report sensitive upper limits extending up to J_upper=50, which place constraints on a previous model prediction for the CO emission from the X-ray obscuring torus. [Abridged]Comment: 20 pages, 10 figures. Accepted for publication in Ap