Spitzer And Herschel Multiwavelength Characterization Of The Dust Content Of Evolved H Ii Regions

We have analyzed a uniform sample of 16 evolved H II regions located in a 2 Degree-Sign Multiplication-Sign 2 Degree-Sign Galactic field centered at (l,b) = (30 Degree-Sign , 0 Degree-Sign ) and observed as part of the Herschel Hi-GAL survey. The evolutionary stage of these H II regions was established using ancillary radio-continuum data. By combining Hi-GAL PACS (70 {mu}m, 160 {mu}m) and SPIRE (250 {mu}m, 350 {mu}m, and 500 {mu}m) measurements with MIPSGAL 24 {mu}m data, we built spectral energy distributions of the sources and showed that a two-component gray-body model is a good representation of the data. In particular, wavelengths \u3e70 {mu}m appear to trace a cold dust component, for which we estimated an equilibrium temperature of the big grains (BGs) in the range 20-30 K, while for {lambda} \u3c 70 {mu}m, the data indicate the presence of a warm dust component at temperatures of the order of 50-90 K. This analysis also revealed that dust is present in the interior of H II regions, although likely not in a large amount. In addition, the data seem to corroborate the hypothesis that the main mechanism responsible for the (partial) depletion of dust in H II regions ismore » radiation-pressure-driven drift. In this framework, we speculated that the 24 {mu}m emission that spatially correlates with ionized gas might be associated with either very small grain or BG replenishment, as recently proposed for the case of wind-blown bubbles. Finally, we found that evolved H II regions are characterized by distinctive far-IR and submillimeter colors, which can be used as diagnostics for their identification in unresolved Galactic and extragalactic regions.« les

Intramedullary craniovertebral junction metastasis leading to the diagnosis of underlying renal cell carcinoma

Background: Intramedullary spinal cord metastases represent 4–8.5% of the central nervous system metastases and affect only 0.1–0.4% of all patients. Those originating from renal cell carcinoma (RCC) are extremely rare. Of the eight patients described in the literature with metastatic RCC and intramedullary cord lesion, only five were found in the cervical spine. Here, the authors add a 6th case involving an RCC intramedullary metastasis at the C1–C2 level. Case Description: A 78-year-old male patient presented with intermittent cervicalgia of 5 months duration accompanied by few weeks of a progressive severe right hemiparesis, up to hemiplegia. The magnetic resonance imaging (MRI) examination revealed an intramedullary expansive lesion measuring 10 mm×15 mm at the C1–C2 level; it readily enhanced with contrast. A total body computed tomography (CT) scan documented an 85 mm mass involving the right kidney, extending to the ipsilateral adrenal gland, and posteriorly infiltrating the ipsilateral psoas muscle. The subsequent CT-guided fine-needle biopsy confirmed the diagnosis of an RCC (Stage IV). The patient next underwent total surgical total removal of the C1–C2 intramedullary mass, following which he exhibited a slight motor improvement, with the right hemiparesis (2/5). He died after 14 months due to global RCC tumor progression. Conclusion: The present case highlights that a patient without a prior known diagnosis of RCC may present with an intramedullary C1–C2 metastasis. In such cases, global staging is critical to determine whether primary lesion resection versus excision of metastases (e.g., in this case, the C1–C2 intramedullary tumor) are warrante

The Radio Corona of AR Lacertae

We present multifrequency VLA and VLBA observations at 8.4 GHz of the RS CVn system AR Lac, that were performed in autumn 1997 simultaneously with X-ray observations obtained from Rodono` et al. (1999). Our VLBA data indicate a resolved source with dimension close to the system separation, while the study of the flux density curve evidences a small amplitude outside of the eclipse variability. The derived five-frequencies spectra, combined with the size information from VLBA data, are compared with gyrosynchrotron emission from a two component structured source. A comparison with the results of the X-ray observations allow us to exclude the possibility that thermal gyrosynchrotron is responsible for the radio emission, but it is compatible with the hypothesis of co-spatial X-ray and radio emitting sources.Comment: 9 pages, 7 figures. Accepted for publication in A&

Spinal hydatidosis relapse: a case report

Human cystic echinococcosis (CE) is a zoonosis caused by the larval stage of the Echinococcus granulosus and the most common sites affected are the liver and lung in approximately 80–90% of cases. The hydatid bone represents the 0.5–2.5% of all cases and localization cord is present about 50% of the time. This benign and commonly asymptomatic disease may simulate an aggressive malignancy because of osseous destruction and aggressive extension. We report a case of a 42-year-old male patient, presented with an unusual spinal hydatidosis relapse, related to anthelmintic drug therapy withdrawal after 10-year treatment. The man had previous excision of chest and hepatic hydatid cysts (resp., 10 and 3 years ago) and after primary mediastinal and spinal involvement (3 years ago) he was lost to follow-up and discontinued drug therapy. The patient underwent surgery and the postoperative histopathology confirmed the diagnosis. The patient recovered with no complications. Despite significant progress in diagnostic imaging, pharmacological and surgical therapy, spinal CE remains associated with high morbidity

New ATCA, ALMA and VISIR observations of the candidate LBV SK-67266 (S61): the nebular mass from modelling 3D density distributions

We present new observations of the nebula around the Magellanic candidate Luminous Blue Variable S61. These comprise high-resolution data acquired with the Australia Telescope Compact Array (ATCA), the Atacama Large Millimetre/Submillimetre Array (ALMA), and VISIR at the Very Large Telescope (VLT). The nebula was detected only in the radio, up to 17 GHz. The 17 GHz ATCA map, with 0.8 arcsec resolution, allowed a morphological comparison with the H$\alpha$ Hubble Space Telescope image. The radio nebula resembles a spherical shell, as in the optical. The spectral index map indicates that the radio emission is due to free-free transitions in the ionised, optically thin gas, but there are hints of inhomogeneities. We present our new public code RHOCUBE to model 3D density distributions, and determine via Bayesian inference the nebula's geometric parameters. We applied the code to model the electron density distribution in the S61 nebula. We found that different distributions fit the data, but all of them converge to the same ionised mass, ~0.1 $\rm M\odot$, which is an order of magnitude smaller than previous estimates. We show how the nebula models can be used to derive the mass-loss history with high-temporal resolution. The nebula was probably formed through stellar winds, rather than eruptions. From the ALMA and VISIR non-detections, plus the derived extinction map, we deduce that the infrared emission observed by space telescopes must arise from extended, diffuse dust within the ionised region.Comment: 17 pages, 9 figures. Authors list corrected. In press in MNRAS. RHOCUBE code available online ( https://github.com/rnikutta/rhocube

In Reply: neurosurgery and coronavirus (COVID-19) epidemic: doing our part

To the Editor: We appreciated the Letter, “Letter: Neurosurgery and Coronavirus (COVID-19) Epidemic: Doing Our Part” by Pesce et al, published in April 2020 in Neurosurgery. We are grateful to the authors of the Letter for their clear analysis of some neurosurgical procedures in the COVID-19 era. Everyone in the neurosurgical community and in the whole medical community is doing their own part to face this terrible pandemic. Specifically, we would like to present our experience with patients needing a lumbar function or a neuroimaging. We already described our strategy for all emergency patients in an article published in Neurosurgery in April 2020 entitled “In Reply: Rongeurs, Neurosurgeons, and COVID-19: How Do We Protect Health Care Personnel During Neurosurgical Operations in the Midst of Aerosol-Generation From High-Speed Drills?

The Luminous Blue Variable RMC127 as seen with ALMA and ATCA

We present ALMA and ATCA observations of the luminous blue variable \rmc. The radio maps show for the first time the core of the nebula and evidence that the nebula is strongly asymmetric with a Z-pattern shape. Hints of this morphology are also visible in the archival \emph{HST} $\rm H\alpha$ image, which overall resembles the radio emission. The emission mechanism in the outer nebula is optically thin free-free in the radio. At high frequencies, a component of point-source emission appears at the position of the star, up to the ALMA frequencies. The rising flux density distribution ($S_{\nu}\sim \nu^{0.78\pm0.05}$) of this object suggests thermal emission from the ionized stellar wind and indicates a departure from spherical symmetry with $n_{e}(r)\propto r^{-2}$. We examine different scenarios to explain this excess of thermal emission from the wind and show that this can arise from a bipolar outflow, supporting the suggestion by other authors that the stellar wind of \rmc is aspherical. We fit the data with two collimated ionized wind models and we find that the mass-loss rate can be a factor of two or more smaller than in the spherical case. We also fit the photometry obtained by IR space telescopes and deduce that the mid- to far-IR emission must arise from extended, cool ($\sim80\,\rm K$) dust within the outer ionized nebula. Finally we discuss two possible scenarios for the nebular morphology: the canonical single star expanding shell geometry, and a precessing jet model assuming presence of a companion star.Comment: Accepted for publication in ApJ (minor revision included

The polarization mode of the auroral radio emission from the early-type star HD142301

We report the detection of the auroral radio emission from the early-type magnetic star HD142301. New VLA observations of HD142301 detected highly polarized amplified emission occurring at fixed stellar orientations. The coherent emission mechanism responsible for the stellar auroral radio emission amplifies the radiation within a narrow beam, making the star where this phenomenon occurs similar to a radio lighthouse. The elementary emission process responsible for the auroral radiation mainly amplifies one of the two magneto-ionic modes of the electromagnetic wave. This explains why the auroral pulses are highly circularly polarized. The auroral radio emission of HD142301 is characterized by a reversal of the sense of polarization as the star rotates. The effective magnetic field curve of HD142301 is also available making it possible to correlate the transition from the left to the right-hand circular polarization sense (and vice-versa) of the auroral pulses with the known orientation of the stellar magnetic field. The results presented in this letter have implications for the estimation of the dominant magneto-ionic mode amplified within the HD142301 magnetosphere.Comment: 5 pages, 4 figures; accepted to MNRAS Letter

SCORPIO-II: Spectral indices of weak Galactic radio sources

In the next few years the classification of radio sources observed by the large surveys will be a challenging problem, and spectral index is a powerful tool for addressing it. Here we present an algorithm to estimate the spectral index of sources from multiwavelength radio images. We have applied our algorithm to SCORPIO (Umana et al. 2015), a Galactic Plane survey centred around 2.1 GHz carried out with ATCA, and found we can measure reliable spectral indices only for sources stronger than 40 times the rms noise. Above a threshold of 1 mJy, the source density in SCORPIO is 20 percent greater than in a typical extra-galactic field, like ATLAS (Norris et al. 2006), because of the presence of Galactic sources. Among this excess population, 16 sources per square degree have a spectral index of about zero, suggesting optically thin thermal emission such as Hii regions and planetary nebulae, while 12 per square degree present a rising spectrum, suggesting optically thick thermal emission such as stars and UCHii regions.Comment: 12 pages, 11 figures, accepted by MNRA

The radio lighthouse CU Virginis: the spindown of a single main sequence star

The fast rotating star CU Virginis is a magnetic chemically peculiar star with an oblique dipolar magnetic field. The continuum radio emission has been interpreted as gyrosyncrotron emission arising from a thin magnetospheric layer. Previous radio observations at 1.4 GHz showed that a 100% circular polarized and highly directive emission component overlaps to the continuum emission two times per rotation, when the magnetic axis lies in the plane of the sky. This sort of radio lighthouse has been proposed to be due to cyclotron maser emission generated above the magnetic pole and propagating perpendicularly to the magnetic axis. Observations carried out with the Australia Telescope Compact Array at 1.4 and 2.5 GHz one year after this discovery show that this radio emission is still present, meaning that the phenomenon responsible for this process is steady on a timescale of years. The emitted radiation spans at least 1 GHz, being observed from 1.4 to 2.5 GHz. On the light of recent results on the physics of the magnetosphere of this star, the possibility of plasma radiation is ruled out. The characteristics of this radio lighthouse provides us a good marker of the rotation period, since the peaks are visible at particular rotational phases. After one year, they show a delay of about 15 minutes. This is interpreted as a new abrupt spinning down of the star. Among several possibilities, a quick emptying of the equatorial magnetic belt after reaching the maximum density can account for the magnitude of the breaking. The study of the coherent emission in stars like CU Vir, as well as in pre main sequence stars, can give important insight into the angular momentum evolution in young stars. This is a promising field of investigation that high sensitivity radio interferometers such as SKA can exploit.Comment: Accepted to MNRAS, 8 pages, 7 figures, updated versio