610 research outputs found
DCO, DCN and ND reveal three different deuteration regimes in the disk around the Herbig Ae star HD163296
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 (=3-2), DCN (=3-2) and ND
(=3-2). We model the radial emission profiles of DCO, DCN and
ND, 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
ND 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 cm
(0.04-0.07), 2.9-5.2 cm (0.02) and 1.6-2.5 cm (0.34-0.45) for DCO, DCN and ND, respectively.
Our simple best-fit models show a correlation between the radial location of
the first two rings in DCO and the DCN and ND 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 HCO production in the outer disk around HD 163296
Three formaldehyde lines were observed (HCO 3--2, HCO
3--2, and HCO 3--2) in the protoplanetary disk
around the Herbig Ae star HD 163296 with ALMA at 0.5 arcsecond (60 AU) spatial
resolution. HCO 3--2 was readily detected via imaging, while
the weaker HCO 3--2 and HCO 3--2 lines
required matched filter analysis to detect. HCO is present throughout most
of the gaseous disk, extending out to 550 AU. An apparent 50 AU inner radius of
the HCO emission is likely caused by an optically thick dust continuum. The
HCO 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 HCO abundance were compared to the observed
visibilities with minimization, using either a characteristic
temperature, a characteristic radius or a radial power law index to describe
the HCO chemistry. Similar models were applied to ALMA Science Verification
data of CO. In all modeling scenarios, fits to the HCO data show an
increased abundance in the outer disk. The overall best-fit HCO model shows
a factor of two enhancement beyond a radius of 27020 AU, with an inner
abundance of . The HCO emitting region has a lower
limit on the kinetic temperature of K. The CO modeling suggests
an order of magnitude depletion in the outer disk and an abundance of in the inner disk. The increase in HCO 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
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
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(optically bright QSO) transition hypothesis
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 , 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 , placing
it firmly on the upper gas-rich/star-forming end of Ultra Luminous Infrared
Galaxies (ULIRGs, ). 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(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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