610 research outputs found

    DCO+^+, DCN and N2_2D+^+ reveal three different deuteration regimes in the disk around the Herbig Ae star HD163296

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    The formation pathways of deuterated species trace different regions of protoplanetary disks and may shed light into their physical structure. We aim to constrain the radial extent of main deuterated species; we are particularly interested in spatially characterizing the high and low temperature pathways for enhancing deuteration of these species. We observed the disk surrounding the Herbig Ae star HD 163296 using ALMA in Band 6 and obtained resolved spectral imaging data of DCO+^+ (JJ=3-2), DCN (JJ=3-2) and N2_2D+^+ (JJ=3-2). We model the radial emission profiles of DCO+^+, DCN and N2_2D+^+, assuming their emission is optically thin, using a parametric model of their abundances and radial excitation temperature estimates. DCO+^+ can be described by a three-region model, with constant-abundance rings centered at 70 AU, 150 AU and 260 AU. The DCN radial profile peaks at about ~60 AU and N2_2D+^+ is seen in a ring at ~160 AU. Simple models of both molecules using constant abundances reproduce the data. Assuming reasonable average excitation temperatures for the whole disk, their disk-averaged column densities (and deuterium fractionation ratios) are 1.6-2.6×1012\times 10^{12} cm2^{-2} (0.04-0.07), 2.9-5.2×1012\times 10^{12} cm2^{-2} (\sim0.02) and 1.6-2.5 ×1011\times 10^{11} cm2^{-2} (0.34-0.45) for DCO+^+, DCN and N2_2D+^+, respectively. Our simple best-fit models show a correlation between the radial location of the first two rings in DCO+^+ and the DCN and N2_2D+^+ abundance distributions that can be interpreted as the high and low temperature deuteration pathways regimes. The origin of the third DCO+^+ ring at 260 AU is unknown but may be due to a local decrease of ultraviolet opacity allowing the photodesorption of CO or due to thermal desorption of CO as a consequence of radial drift and settlement of dust grains

    Increased H2_2CO production in the outer disk around HD 163296

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    Three formaldehyde lines were observed (H2_2CO 303_{03}--202_{02}, H2_2CO 322_{22}--221_{21}, and H2_2CO 321_{21}--220_{20}) in the protoplanetary disk around the Herbig Ae star HD 163296 with ALMA at 0.5 arcsecond (60 AU) spatial resolution. H2_2CO 303_{03}--202_{02} was readily detected via imaging, while the weaker H2_2CO 322_{22}--221_{21} and H2_2CO 321_{21}--220_{20} lines required matched filter analysis to detect. H2_2CO is present throughout most of the gaseous disk, extending out to 550 AU. An apparent 50 AU inner radius of the H2_2CO emission is likely caused by an optically thick dust continuum. The H2_2CO radial intensity profile shows a peak at 100 AU and a secondary bump at around 300 AU, suggesting increased production in the outer disk. Different parameterizations of the H2_2CO abundance were compared to the observed visibilities with χ2\chi^2 minimization, using either a characteristic temperature, a characteristic radius or a radial power law index to describe the H2_2CO chemistry. Similar models were applied to ALMA Science Verification data of C18^{18}O. In all modeling scenarios, fits to the H2_2CO data show an increased abundance in the outer disk. The overall best-fit H2_2CO model shows a factor of two enhancement beyond a radius of 270±\pm20 AU, with an inner abundance of 2 ⁣ ⁣5×10122\!-\!5 \times 10^{-12}. The H2_2CO emitting region has a lower limit on the kinetic temperature of T>20T > 20 K. The C18^{18}O modeling suggests an order of magnitude depletion in the outer disk and an abundance of 4 ⁣ ⁣12×1084\!-\!12 \times 10^{-8} in the inner disk. The increase in H2_2CO outer disk emission could be a result of hydrogenation of CO ices on dust grains that are then sublimated via thermal desorption or UV photodesorption, or more efficient gas-phase production beyond about 300 AU if CO is photodisocciated in this region

    Effect of the patient information brochure in communicating the risks associated with crizotinib treatment to patients with non-small cell lung cancer (NSCLC) in Europe

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    Crizotinib (XALKORI®) is indicated for anaplastic lymphoma kinase-positive and ROS1-positive advanced non-small cell lung cancer. This study evaluated the distribution of the crizotinib patient information brochure (PIB) in Europe and patient knowledge of the key messages in the PIB. A cross-sectional survey was conducted in 10 European countries among patients who received crizotinib to ascertain whether each patient received and read the PIB, and his/her knowledge of its key messages on hepatotoxicity, interstitial lung disease/pneumonitis, QTc prolongation, bradycardia, and vision disorders. Of the 341 patients contacted, 40 responded (11.7%), and 39 patients were eligible. A total of 77% of respondents acknowledged receiving the PIB, of which, 93% reported reading it. Knowledge of the individual side effects ranged from 36% to 85%, and precautions for use ranged from 56% to 67%. Understanding the reasons for calling a physician ranged from 54% to 85%. Knowledge of each of the 6 key side effects was greater among readers of the PIB compared to non-readers or respondents who did not recall receiving the PIB. Approximately three-quarters of survey respondents recalled receiving the crizotinib PIB and respondents who read the PIB were more knowledgeable of the key side effects of crizotinib than those who did not read or receive. Caution should be taken in generalizing these results because of the potential for selection bias and small sample size. These survey results suggest that the crizotinib PIB may be an effective risk communication tool for crizotinib-treated patients in Europe

    Asteroid Belts in Debris Disk Twins: VEGA and FOMALHAUT

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    Vega and Fomalhaut, are similar in terms of mass, ages, and global debris disk properties; therefore, they are often referred as "debris disk twins". We present Spitzer 10-35 um spectroscopic data centered at both stars, and identify warm, unresolved excess emission in the close vicinity of Vega for the first time. The properties of the warm excess in Vega are further characterized with ancillary photometry in the mid infrared and resolved images in the far-infrared and submillimeter wavelengths. The Vega warm excess shares many similar properties with the one found around Fomalhaut. The emission shortward of ~30 um from both warm components is well described as a blackbody emission of ~170 K. Interestingly, two other systems, eps Eri and HR 8799, also show such an unresolved warm dust using the same approach. These warm components may be analogous to the solar system's zodiacal dust cloud, but of far greater. The dust temperature and tentative detections in the submillimeter suggest the warm excess arises from dust associated with a planetesimal ring located near the water-frost line and presumably created by processes occurring at similar locations in other debris systems as well. We also review the properties of the 2 um hot excess around Vega and Fomalhaut, showing that the dust responsible for the hot excess is not spatially associated with the dust we detected in the warm belt. We suggest it may arise from hot nano grains trapped in the magnetic field of the star. Finally, the separation between the warm and cold belt is rather large with an orbital ratio >~10 in all four systems. In light of the current upper limits on the masses of planetary objects and the large gap, we discuss the possible implications for their underlying planetary architecture, and suggest that multiple, low-mass planets likely reside between the two belts in Vega and Fomalhaut.Comment: 14 pages, accepted for publication in Ap

    A new twist to an old story: HE 0450-2958, and the ULIRG\to (optically bright QSO) transition hypothesis

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    We report on interferometric imaging of the CO J=1--0 and J=3--2 line emission from the controversial QSO/galaxy pair HE 0450--2958. {\it The detected CO J=1--0 line emission is found associated with the disturbed companion galaxy not the luminous QSO,} and implies Mgal(H2)(12)×1010M\rm M_{gal}(H_2)\sim (1-2)\times 10^{10} M_{\odot}, which is \ga 30% of the dynamical mass in its CO-luminous region. Fueled by this large gas reservoir this galaxy is the site of an intense starburst with SFR370Myr1\rm SFR\sim 370 M_{\odot} yr^{-1}, placing it firmly on the upper gas-rich/star-forming end of Ultra Luminous Infrared Galaxies (ULIRGs, LIR>1012L\rm L_{IR}>10^{12} L_{\odot}). This makes HE 0450--2958 the first case of extreme starburst and powerful QSO activity, intimately linked (triggered by a strong interaction) but not coincident. The lack of CO emission towards the QSO itself renews the controversy regarding its host galaxy by making a gas-rich spiral (the typical host of Narrow Line Seyfert~1 AGNs) less likely. Finally, given that HE 0450--2958 and similar IR-warm QSOs are considered typical ULIRG\to (optically bright QSO) transition candidates, our results raise the possibility that some may simply be {\it gas-rich/gas-poor (e.g. spiral/elliptical) galaxy interactions} which ``activate'' an optically bright unobscured QSO in the gas-poor galaxy, and a starburst in the gas-rich one. We argue that such interactions may have gone largely unnoticed even in the local Universe because the combination of tools necessary to disentagle the progenitors (high resolution and S/N optical {\it and} CO imaging) became available only recently.Comment: 25 pages, 5 figures, accepted for publication by The Astrophysical Journa
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