The Dispersion Velocity of Galactic Dark Matter Particles

The self-consistent spatial distribution of particles of Galactic dark matter is derived including their own gravitational potential, as also that of the visible matter of the Galaxy. In order to reproduce the observed rotation curve of the Galaxy the value of the dispersion velocity of the dark matter particles, \rmsveldm, should be \sim 600\kmps or larger.Comment: RevTex, 4 pages, 1 ps figure, accepted for publication in Physical Review Letter

DERMATOFITOSIS. ETIOLOGIA Y SUSCEPTIBILIDAD ANTIFUNGICA “IN VITRO” EN TRES CENTROS HOSPITALARIOS DE SANTIAGO (CHILE)

Con el objetivo de determinar la frecuencia de dermatofitos en lesiones sospechosas de micosis y evaluar su susceptibilidad “in vitro” frente a Clotrimazol (CLZ), Itraconazol (ITZ), Griseofulvina (GRI), Fluconazol(FCZ) y Terbinafina (TBF), se recolectaron 175 muestras (piel, pelo y uñas ) y datos epidemiológicos de cada paciente. El diagnóstico micológico se realizó mediante: un examen directo con KOH al 20% y cultivo en agar Sabouraud y Lactrimel, incubados a 25º y 37º por 21días. La susceptibilidad “in vitro” se realizó por el método de microdilución en caldo según recomendaciones NCCLS (documento M38-P), determinándose CIM 50 y CIM90.El examen directo fue positivo en e l 73,7% (n=129) de las muestras y el cultivo en 66,3% (n=116), aumentando a un 80,6% (n=141) al usar ambas técnicas. Los agentes aislados correspondieron a Trichophytonrubrum (81%), T. mentagrophytes(14,7%) y Microsporum canis (4,3%). En 110 cepas, la CIM50 para FCZ fue 0,25 μg/mL y 0,03 μg/mL para GRI, ITZ, CLZ y TBF. La CIM90 de FCZ fue 2,0 μg/mL, 0,12 μg/mL para ITZ y 0,06 μg/mL para CLZ, GRI y TBF.En general, los antifúngicos probados fueron activos frente a las cepas aisladas, excepto 2 cepas que mostraron CIM elevadas para ITZ.

A study of the neglected Galactic HII region NGC 2579 and its companion ESO 370-9

The Galactic HII region NGC 2579 has stayed undeservedly unexplored due to identification problems which persisted until recently. Both NGC 2579 and its companion ESO 370-9 have been misclassified as planetary or reflection nebula, confused with each other and with other objects. Due to its high surface brightness, high excitation, angular size of few arcminutes and relatively low interstellar extinction, NGC 2579 is an ideal object for investigations in the optical range. Located in the outer Galaxy, NGC 2579 is an excellent object for studying the Galactic chemical abundance gradients. In this paper we present the first comprehensive observational study on the nebular and stellar properties of NGC 2579 and ESO 370-9, including the determination of electron temperature, density structure, chemical composition, kinematics, distance, and the identification and spectral classification of the ionizing stars, and discuss the nature of ESO 370-9. Long slit spectrophotometric data in the optical range were used to derive the nebular electron temperature, density and chemical abundances and for the spectral classification of the ionizing star candidates. Halpha and UBV CCD photometry was carried out to derive stellar distances from spectroscopic parallax and to measure the ionizing photon flux.Comment: To be published in Astronomy & Astrophysic

Herschel observations in the ultracompact HII region Mon R2: Water in dense Photon-dominated regions (PDRs)

Mon R2, at a distance of 830 pc, is the only ultracompact HII region (UC HII) where the photon-dominated region (PDR) between the ionized gas and the molecular cloud can be resolved with Herschel. HIFI observations of the abundant compounds 13CO, C18O, o-H2-18O, HCO+, CS, CH, and NH have been used to derive the physical and chemical conditions in the PDR, in particular the water abundance. The 13CO, C18O, o-H2-18O, HCO+ and CS observations are well described assuming that the emission is coming from a dense (n=5E6 cm-3, N(H2)>1E22 cm-2) layer of molecular gas around the UC HII. Based on our o-H2-18O observations, we estimate an o-H2O abundance of ~2E-8. This is the average ortho-water abundance in the PDR. Additional H2-18O and/or water lines are required to derive the water abundance profile. A lower density envelope (n~1E5 cm-3, N(H2)=2-5E22 cm-2) is responsible for the absorption in the NH 1_1-0_2 line. The emission of the CH ground state triplet is coming from both regions with a complex and self-absorbed profile in the main component. The radiative transfer modeling shows that the 13CO and HCO+ line profiles are consistent with an expansion of the molecular gas with a velocity law, v_e =0.5 x (r/Rout)^{-1} km/s, although the expansion velocity is poorly constrained by the observations presented here.Comment: 4 pages, 5 figure

HERSCHEL-HIFI spectroscopy of the intermediate mass protostar NGC7129 FIRS 2

HERSCHEL-HIFI observations of water from the intermediate mass protostar NGC7129 FIRS 2 provide a powerful diagnostic of the physical conditions in this star formation environment. Six spectral settings, covering four H216O and two H218O lines, were observed and all but one H218O line were detected. The four H2 16 O lines discussed here share a similar morphology: a narrower, \approx 6 km/s, component centered slightly redward of the systemic velocity of NGC7129 FIRS 2 and a much broader, \approx 25 km/s component centered blueward and likely associated with powerful outflows. The narrower components are consistent with emission from water arising in the envelope around the intermediate mass protostar, and the abundance of H2O is constrained to \approx 10-7 for the outer envelope. Additionally, the presence of a narrow self-absorption component for the lowest energy lines is likely due to self-absorption from colder water in the outer envelope. The broader component, where the H2O/CO relative abundance is found to be \approx 0.2, appears to be tracing the same energetic region that produces strong CO emission at high J.Comment: 6 pages, 4 figures, accepted by A&

Submillimeter Emission from Water in the W3 Region

We have mapped the submillimeter emission from the 1(10)-1(01) transition of ortho-water in the W3 star-forming region. A 5'x5' map of the W3 IRS4 and W3 IRS5 region reveals strong water lines at half the positions in the map. The relative strength of the Odin lines compared to previous observations by SWAS suggests that we are seeing water emission from an extended region. Across much of the map the lines are double-peaked, with an absorption feature at -39 km/s; however, some positions in the map show a single strong line at -43 km/s. We interpret the double-peaked lines as arising from optically thick, self-absorbed water emission near the W3 IRS5, while the narrower blue-shifted lines originate in emission near W3 IRS4. In this model, the unusual appearance of the spectral lines across the map results from a coincidental agreement in velocity between the emission near W3 IRS4 and the blue peak of the more complex lines near W3 IRS5. The strength of the water lines near W3 IRS4 suggests we may be seeing water emission enhanced in a photon-dominated region.Comment: Accepted to A&A Letters as part of the special Odin issue; 4 page

Herschel observations of the hydroxyl radical (OH) in young stellar objects

Water in Star-forming regions with Herschel (WISH) is a Herschel Key Program investigating the water chemistry in young stellar objects (YSOs) during protostellar evolution. Hydroxyl (OH) is one of the reactants in the chemical network most closely linked to the formation and destruction of H2O. High-temperature chemistry connects OH and H2O through the OH + H2 H2O + H reactions. Formation of H2O from OH is efficient in the high-temperature regime found in shocks and the innermost part of protostellar envelopes. Moreover, in the presence of UV photons, OH can be produced from the photo-dissociation of H2O. High-resolution spectroscopy of the OH 163.12 micron triplet towards HH 46 and NGC 1333 IRAS 2A was carried out with the Heterodyne Instrument for the Far Infrared (HIFI) on board Herschel. The low- and intermediate-mass YSOs HH 46, TMR 1, IRAS 15398-3359, DK Cha, NGC 7129 FIRS 2, and NGC 1333 IRAS 2A were observed with the Photodetector Array Camera and Spectrometer (PACS) in four transitions of OH and two [OI] lines. The OH transitions at 79, 84, 119, and 163 micron and [OI] emission at 63 and 145 micron were detected with PACS towards the class I low-mass YSOs as well as the intermediate-mass and class I Herbig Ae sources. No OH emission was detected from the class 0 YSO NGC 1333 IRAS 2A, though the 119 micron was detected in absorption. With HIFI, the 163.12 micron was not detected from HH 46 and only tentatively detected from NGC 1333 IRAS 2A. The combination of the PACS and HIFI results for HH 46 constrains the line width (FWHM > 11 km/s) and indicates that the OH emission likely originates from shocked gas. This scenario is supported by trends of the OH flux increasing with the [OI] flux and the bolometric luminosity. Similar OH line ratios for most sources suggest that OH has comparable excitation temperatures despite the different physical properties of the sources.Comment: Accepted for publication in Astronomy and Astrophysics (Herschel special issue

Strong CH+ J=1-0 emission and absorption in DR21

We report the first detection of the ground-state rotational transition of the methylidyne cation CH+ towards the massive star-forming region DR21 with the HIFI instrument onboard the Herschel satellite. The line profile exhibits a broad emission line, in addition to two deep and broad absorption features associated with the DR21 molecular ridge and foreground gas. These observations allow us to determine a CH+ J=1-0 line frequency of 835137 +/- 3 MHz, in good agreement with a recent experimental determination. We estimate the CH+ column density to be a few 1e13 cm^-2 in the gas seen in emission, and > 1e14 cm^-2 in the components responsible for the absorption, which is indicative of a high line of sight average abundance [CH+]/[H] > 1.2x10^-8. We show that the CH+ column densities agree well with the predictions of state-of-the-art C-shock models in dense UV-illuminated gas for the emission line, and with those of turbulent dissipation models in diffuse gas for the absorption lines.Comment: Accepted for publication in A&

Sensitive limits on the abundance of cold water vapor in the DM Tau protoplanetary disk

We performed a sensitive search for the ground-state emission lines of ortho- and para-water vapor in the DM Tau protoplanetary disk using the Herschel/HIFI instrument. No strong lines are detected down to 3sigma levels in 0.5 km/s channels of 4.2 mK for the 1_{10}--1_{01} line and 12.6 mK for the 1_{11}--0_{00} line. We report a very tentative detection, however, of the 1_{10}--1_{01} line in the Wide Band Spectrometer, with a strength of T_{mb}=2.7 mK, a width of 5.6 km/s and an integrated intensity of 16.0 mK km/s. The latter constitutes a 6sigma detection. Regardless of the reality of this tentative detection, model calculations indicate that our sensitive limits on the line strengths preclude efficient desorption of water in the UV illuminated regions of the disk. We hypothesize that more than 95-99% of the water ice is locked up in coagulated grains that have settled to the midplane.Comment: 5 pages, 3 figures. Accepted for publication in the Herschel HIFI special issue of A&