A long-term spectroscopic and photometric survey of the most luminous and massive stars in the vicinity of the supermassive black hole Sgr A* revealed two new binaries: a long-period Ofpe/WN9 binary, ...IRS 16NE, with a modest eccentricity of 0.3 and a period of 224 days, and an eclipsing Wolf-Rayet binary with a period of 2.3 days. Together with the already identified binary IRS 16SW, there are now three confirmed OB/WR binaries in the inner 0.2 pc of the Galactic center. Using radial velocity change upper limits, we were able to constrain the spectroscopic binary fraction in the Galactic center to F sub(SB) = 0.30 super(+0.34) sub(-0.21) at a confidence level of 95%, a massive binary fraction close to that observed in dense clusters. The fraction of eclipsing binaries with photometric amplitudes Delta m > 0.4 is F super(GC) sub(EB) = 3% + or - 2%, which is consistent with local OB star clusters (F sub(EB) = 1%). Overall, the Galactic center binary fraction seems to be similar to the binary fraction in comparable young clusters.
Context.
Methods used to detect giant exoplanets can be broadly divided into two categories: indirect and direct. Indirect methods are more sensitive to planets with a small orbital period, whereas ...direct detection is more sensitive to planets orbiting at a large distance from their host star. This dichotomy makes it difficult to combine the two techniques on a single target at once.
Aims.
Simultaneous measurements made by direct and indirect techniques offer the possibility of determining the mass and luminosity of planets and a method of testing formation models. Here, we aim to show how long-baseline interferometric observations guided by radial-velocity can be used in such a way.
Methods.
We observed the recently-discovered giant planet
β
Pictoris c with GRAVITY, mounted on the Very Large Telescope Interferometer.
Results.
This study constitutes the first direct confirmation of a planet discovered through radial velocity. We find that the planet has a temperature of
T
= 1250 ± 50 K and a dynamical mass of
M
= 8.2 ± 0.8
M
Jup
. At 18.5 ± 2.5 Myr, this puts
β
Pic c close to a ‘hot start’ track, which is usually associated with formation via disk instability. Conversely, the planet orbits at a distance of 2.7 au, which is too close for disk instability to occur. The low apparent magnitude (
M
K
= 14.3 ± 0.1) favours a core accretion scenario.
Conclusions.
We suggest that this apparent contradiction is a sign of hot core accretion, for example, due to the mass of the planetary core or the existence of a high-temperature accretion shock during formation.
We present a study of the X-ray flaring activity of Sgr A⋆ during all the 150 XMM–Newton and Chandra observations pointed at the Milky Way centre over the last 15 years. This includes the latest ...XMM–Newton and Chandra campaigns devoted to monitoring the closest approach of the very red Brγ emitting object called G2. The entire data set analysed extends from 1999 September through 2014 November. We employed a Bayesian block analysis to investigate any possible variations in the characteristics (frequency, energetics, peak intensity, duration) of the flaring events that Sgr A⋆ has exhibited since their discovery in 2001. We observe that the total bright or very bright flare luminosity of Sgr A⋆ increased between 2013 and 2014 by a factor of 2–3 (∼3.5σ significance). We also observe an increase (∼99.9 per cent significance) from 0.27 ± 0.04 to 2.5 ± 1.0 d−1 of the bright or very bright flaring rate of Sgr A⋆, starting in late summer 2014, which happens to be about six months after G2's pericentre passage. This might indicate that clustering is a general property of bright flares and that it is associated with a stationary noise process producing flares not uniformly distributed in time (similar to what is observed in other quiescent black holes). If so, the variation in flaring properties would be revealed only now because of the increased monitoring frequency. Alternatively, this may be the first sign of an excess accretion activity induced by the close passage of G2. More observations are necessary to distinguish between these two hypotheses.
Radiotheranostics is a field of rapid growth with some approved treatments including 131I for thyroid cancer, 223Ra for osseous metastases, 177Lu-DOTATATE for neuroendocrine tumors, and 177Lu-PSMA ...(prostate-specific membrane antigen) for prostate cancer, and several more under investigation. In this review, we will cover the fundamentals of radiotheranostics, the key clinical studies that have led to current success, future developments with new targets, radionuclides and platforms, challenges with logistics and reimbursement and, lastly, forthcoming considerations regarding dosimetry, identifying the right line of therapy, artificial intelligence and more.
•The fundamentals of radiotheranostics, established therapies, and key clinical studies.•Future developments: new targets, new radionuclides, new platforms, and synergistic combination therapies.•Challenges: shortages in radionuclides and qualified professionals, efficient patient flow, and reimbursement.•Forthcoming considerations: dose limits, dosimetry-based therapy, new lines of therapy, complementary role with immunotherapy, and artificial intelligence.
We have further followed the evolution of the orbital and physical properties of G2, the object currently falling toward the massive black hole in the Galactic Center on a near-radial orbit. New, ...very sensitive data were taken in 2013 April with NACO and SINFONI at the ESO VLT. The "head" of G2 continues to be stretched ever further along the orbit in position-velocity space. A fraction of its emission appears to be already emerging on the blueshifted side of the orbit, past pericenter approach. Ionized gas in the head is now stretched over more than 15,000 Schwarzschild radii R sub(S) around the pericenter of the orbit, at approx =2000 R sub(S) approx = 20 light hours from the black hole. The pericenter passage of G2 will be a process stretching over a period of at least one year. The Brackett- gamma luminosity of the head has been constant over the past nine years, to within + or -25%, as have the line ratios Brackett- gamma /Paschen- alpha and Brackett- gamma /Helium-I. We do not see any significant evidence for deviations of G2's dynamical evolution due to hydrodynamical interactions with the hot gas around the black hole from a ballistic orbit of an initially compact cloud with moderate velocity dispersion. The constant luminosity and the increasingly stretched appearance of the head of G2 in the position-velocity plane, without a central peak, is not consistent with several proposed models with continuous gas release from an initially bound zone around a faint star on the same orbit as G2.
We present new near-infrared VLTI/GRAVITY interferometric spectra that spatially resolve the broad Br
γ
emission line in the nucleus of the active galaxy IRAS 09149−6206. We use these data to measure ...the size of the broad line region (BLR) and estimate the mass of the central black hole. Using an improved phase calibration method that reduces the differential phase uncertainty to 0.05° per baseline across the spectrum, we detect a differential phase signal that reaches a maximum of ∼0.5° between the line and continuum. This represents an offset of ∼120
μ
as (0.14 pc) between the BLR and the centroid of the hot dust distribution traced by the 2.3
μ
m continuum. The offset is well within the dust sublimation region, which matches the measured ∼0.6 mas (0.7 pc) diameter of the continuum. A clear velocity gradient, almost perpendicular to the offset, is traced by the reconstructed photocentres of the spectral channels of the Br
γ
line. We infer the radius of the BLR to be ∼65
μ
as (0.075 pc), which is consistent with the radius–luminosity relation of nearby active galactic nuclei derived based on the time lag of the H
β
line from reverberation mapping campaigns. Our dynamical modelling indicates the black hole mass is ∼1 × 10
8
M
⊙
, which is a little below, but consistent with, the standard
M
BH
–
σ
*
relation.
We study the short-term effects of an intermediate-mass black hole (IBH) on the orbit of star S2 (S02), the shortest period star known to orbit the supermassive black hole (MBH) in the centre of the ...Milky Way. Near-infrared imaging and spectroscopic observations allow an accurate determination of the orbit of the star. Given S2’s short orbital period and large eccentricity, general relativity (GR) needs to be taken into account, and its effects are potentially measurable with current technology. We show that perturbations due to an IBH in orbit around the MBH can produce a shift in the apoapsis of S2 that is as large or even larger than the GR shift. An IBH will also induce changes in the plane of S2’s orbit at a level as large as 1° per period. We apply observational orbital fitting techniques to simulations of the S-cluster in the presence of an IBH and find that an IBH more massive than about 1000 M at the distance of the S-stars will be detectable at the next periapse passage of S2, which will occur in 2018.
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