ORCID Profile
0000-0002-2554-1837
Current Organisations
Technical University of Denmark
,
Medicines Evaluation Board
,
Universiteit Utrecht
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Publisher: American Astronomical Society
Date: 20-08-2012
Publisher: Springer Science and Business Media LLC
Date: 24-07-2023
DOI: 10.1038/S41586-023-06317-9
Abstract: Terrestrial and sub-Neptune planets are expected to form in the inner (less than 10 au ) regions of protoplanetary disks 1 . Water plays a key role in their formation 2–4 , although it is yet unclear whether water molecules are formed in situ or transported from the outer disk 5,6 . So far Spitzer Space Telescope observations have only provided water luminosity upper limits for dust-depleted inner disks 7 , similar to PDS 70, the first system with direct confirmation of protoplanet presence 8,9 . Here we report JWST observations of PDS 70, a benchmark target to search for water in a disk hosting a large (approximately 54 au ) planet-carved gap separating an inner and outer disk 10,11 . Our findings show water in the inner disk of PDS 70. This implies that potential terrestrial planets forming therein have access to a water reservoir. The column densities of water vapour suggest in-situ formation via a reaction sequence involving O, H 2 and/or OH, and survival through water self-shielding 5 . This is also supported by the presence of CO 2 emission, another molecule sensitive to ultraviolet photodissociation. Dust shielding, and replenishment of both gas and small dust from the outer disk, may also play a role in sustaining the water reservoir 12 . Our observations also reveal a strong variability of the mid-infrared spectral energy distribution, pointing to a change of inner disk geometry.
Publisher: Elsevier BV
Date: 11-2021
DOI: 10.1016/J.EJCA.2021.08.044
Abstract: Little is known about outcomes of adjuvant-treated melanoma patients beyond the clinical trial setting. Since 2019, adjuvant-treated melanoma patients have been registered in the DMTR, a population-based registry to monitor the quality and safety of melanoma care in the Netherlands. This study aims to describe treatment patterns, relapse, and toxicity rates of adjuvant-treated melanoma patients beyond the clinical trial setting. Analyses were performed on adjuvant-treated melanoma patients included in the DMTR. Descriptive statistics were used to analyse patient-, and treatment characteristics. A baseline registration completeness analysis was performed, and an analysis on trial eligibility in clinical practice patients. Recurrence-free survival (RFS) at 12-months was estimated with the Kaplan-Meier method. A total of 641 patients were treated with adjuvant anti-PD-1 therapy. RFS at 12-months was 70.6% (95% CI, 66.9-74.6) with a median follow-up of 12.8 months. Sex, stage of disease and Breslow thickness were associated with a higher hazard for RFS. Eighteen per cent of the anti-PD-1-treated patients developed grade ≥3 toxicity. Sixty-one per cent of patients prematurely discontinued anti-PD-1 therapy. Adjuvant anti-PD-1 treatment of resected stage III/IV melanoma in daily practice showed slightly higher toxicity rates and more frequent premature discontinuation but similar RFS rates compared to trials.
Publisher: American Astronomical Society
Date: 25-06-2018
Publisher: American Astronomical Society
Date: 04-2023
Abstract: We present JWST-MIRI Medium Resolution Spectrometer (MRS) spectra of the protoplanetary disk around the low-mass T Tauri star GW Lup from the MIRI mid-INfrared Disk Survey Guaranteed Time Observations program. Emission from 12 CO 2 , 13 CO 2 , H 2 O, HCN, C 2 H 2 , and OH is identified with 13 CO 2 being detected for the first time in a protoplanetary disk. We characterize the chemical and physical conditions in the inner few astronomical units of the GW Lup disk using these molecules as probes. The spectral resolution of JWST-MIRI MRS paired with high signal-to-noise data is essential to identify these species and determine their column densities and temperatures. The Q branches of these molecules, including those of hot bands, are particularly sensitive to temperature and column density. We find that the 12 CO 2 emission in the GW Lup disk is coming from optically thick emission at a temperature of ∼400 K. 13 CO 2 is optically thinner and based on a lower temperature of ∼325 K, and thus may be tracing deeper into the disk and/or a larger emitting radius than 12 CO 2 . The derived N CO 2 / N H 2 O ratio is orders of magnitude higher than previously derived for GW Lup and other targets based on Spitzer-InfraRed-Spectrograph data. This high column density ratio may be due to an inner cavity with a radius in between the H 2 O and CO 2 snowlines and/or an overall lower disk temperature. This paper demonstrates the unique ability of JWST to probe inner disk structures and chemistry through weak, previously unseen molecular features.
Publisher: American Astronomical Society
Date: 06-08-2012
Publisher: Oxford University Press (OUP)
Date: 15-12-2011
Publisher: American Astronomical Society
Date: 28-03-2013
Publisher: American Astronomical Society
Date: 12-03-2010
Publisher: Oxford University Press (OUP)
Date: 24-03-2020
Abstract: To study the high-transition dense-gas tracers and their relationships to the star formation of the inner ∼2 kpc circumnuclear region of NGC 253, we present HCN J = 4−3 and HCO+ J = 4−3 maps obtained with the James Clerk Maxwell Telescope. Using the spatially resolved data, we compute the concentration indices r90/r50 for the different tracers. HCN and HCO+ 4–3 emission features tend to be centrally concentrated, which is in contrast to the shallower distribution of CO 1–0 and the stellar component. The dense-gas fraction (fdense, traced by the velocity-integrated-intensity ratios of HCN/CO and HCO+/CO) and the ratio R31 (CO 3–2/1–0) decline towards larger galactocentric distances, but increase with higher star formation rate surface density. The radial variation and the large scatter of fdense and R31 imply distinct physical conditions in different regions of the galactic disc. The relationships of fdense versus Σstellar, and SFEdense versus Σstellar are explored. SFEdense increases with higher Σstellar in this galaxy, which is inconsistent with previous work that used HCN 1–0 data. This implies that existing stellar components might have different effects on the high-J HCN and HCO+ than their low-J emission. We also find that SFEdense seems to be decreasing with higher fdense which is consistent with previous works, and it suggests that the ability of the dense gas to form stars diminishes when the average density of the gas increases. This is expected in a scenario where only the regions with high-density contrast collapse and form stars.
Publisher: IOP Publishing
Date: 30-07-2012
Publisher: Oxford University Press (OUP)
Date: 08-08-2012
Publisher: Oxford University Press (OUP)
Date: 13-08-2021
Abstract: Galaxy clusters provide an excellent probe in various research fields in astrophysics and cosmology. However, the number of galaxy clusters detected so far in the AKARI North Ecliptic Pole (NEP) field is limited. In this work, we provide galaxy cluster candidates in the AKARI NEP field with the minimum requisites based only on the coordinates and photometric redshift (photo-z) of galaxies. We used galaxies detected in five optical bands (g, r, i, z, and Y) by the Subaru Hyper Suprime-Cam (HSC), with additional data from the u band obtained from the Canada-France-Hawaii Telescope (CFHT) MegaPrime/MegaCam, and from the IRAC1 and IRAC2 bands from the Spitzer space telescope for photo-z estimation. We calculated the local density around every galaxy using the 10th-nearest neighbourhood. Cluster candidates were determined by applying the friends-of-friends algorithm to over-densities. A total of 88 cluster candidates containing 4390 member galaxies below redshift 1.1 in 5.4 deg2 were identified. The reliability of our method was examined through false-detection tests, redshift-uncertainty tests, and applications on the Cosmic Evolution Survey (COSMOS) data, giving false-detection rates of 0.01 to 0.05 and a recovery rate of 0.9 at high richness. Three X-ray clusters previously observed by ROSAT and Chandra were recovered. The cluster galaxies show a higher stellar mass and lower star formation rate compared with the field galaxies in two-s le Z-tests. These cluster candidates are useful for environmental studies of galaxy evolution and future astronomical surveys in the NEP, where AKARI has performed unique nine-band mid-infrared photometry for tens of thousands of galaxies.
Publisher: American Astronomical Society
Date: 04-04-2014
Publisher: American Astronomical Society
Date: 13-05-2019
Publisher: Oxford University Press (OUP)
Date: 07-03-2013
Publisher: Oxford University Press (OUP)
Date: 14-01-2014
Publisher: American Astronomical Society
Date: 04-04-2013
Publisher: Springer Science and Business Media LLC
Date: 03-2013
DOI: 10.1038/NATURE12001
Abstract: In the past decade, our understanding of galaxy evolution has been revolutionized by the discovery that luminous, dusty starburst galaxies were 1,000 times more abundant in the early Universe than at present. It has, however, been difficult to measure the complete redshift distribution of these objects, especially at the highest redshifts (z > 4). Here we report a redshift survey at a wavelength of three millimetres, targeting carbon monoxide line emission from the star-forming molecular gas in the direction of extraordinarily bright millimetre-wave-selected sources. High-resolution imaging demonstrates that these sources are strongly gravitationally lensed by foreground galaxies. We detect spectral lines in 23 out of 26 sources and multiple lines in 12 of those 23 sources, from which we obtain robust, unambiguous redshifts. At least 10 of the sources are found to lie at z > 4, indicating that the fraction of dusty starburst galaxies at high redshifts is greater than previously thought. Models of lens geometries in the s le indicate that the background objects are ultra-luminous infrared galaxies, powered by extreme bursts of star formation.
Publisher: Oxford University Press (OUP)
Date: 22-11-2012
DOI: 10.1093/MNRAS/STS264
Publisher: American Astronomical Society
Date: 26-11-2013
Publisher: Oxford University Press (OUP)
Date: 21-05-2013
DOI: 10.1093/MNRAS/STT741
Location: United Kingdom of Great Britain and Northern Ireland
Location: United States of America
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Thomas R. Greve.