50 research outputs found
The recurrence of disease activity after ocrelizumab discontinuation in multiple sclerosis
Introduction: Ocrelizumab (OCR) is a highly effective treatment of multiple sclerosis (MS), and B cell repopulation profiles suggest that it might be used as an immune reconstitution therapy. However, data on disease recurrence after stopping treatment with OCR are scarce. Our objective was to evaluate the recurrence of disease activity after OCR discontinuation.Methods: In this multicenter retrospective cohort study, we included MS patients who discontinued OCR, without switching to another treatment, for twelve months or more, after having received at least one full dosage of 600 mg. We defined focal inflammation as the occurrence of a clinical relapse or significant MRI activity (≥3 new T2 lesions or ≥2 contrast-enhancing lesions). Results: We included 53 MS patients; 41 relapsing remitting (RRMS), 5 secondary progressive (SPMS) and 7 primary progressive (PPMS) patients. Median follow-up period after OCR discontinuation was 16 months. We only observed focal inflammation after discontinuation in RRMS patients; 2.4 % (1/41) patients presented with significant MRI activity and matching clinical symptoms, and 7.3 % (3/41) patients presented with a suspected clinical relapse without radiological activity: a total of 9.8 % (4/41) at a median time of 17 months after the last infusion. Discussion: We found focal inflammation after discontinuation of OCR in 4 (9.8 %) of the RRMS patients, of which 1 was radiologically confirmed. Our observations highlight that recurrence of focal inflammation seems low but discontinuation may not be appropriate for everyone. Further larger studies are important to determine the immune reconstitution therapy potential of OCR.</p
A Measurement of the CMB Temperature Power Spectrum and Constraints on Cosmology from the SPT-3G 2018 TT/TE/EE Data Set
We present a sample-variance-limited measurement of the temperature power
spectrum () of the cosmic microwave background (CMB) using observations of
a field made by SPT-3G in 2018. We report
multifrequency power spectrum measurements at 95, 150, and 220GHz covering the
angular multipole range . We combine this
measurement with the published polarization power spectrum measurements from
the 2018 observing season and update their associated covariance matrix to
complete the SPT-3G 2018 data set. This is the first analysis to
present cosmological constraints from SPT , , and power spectrum
measurements jointly. We blind the cosmological results and subject the data
set to a series of consistency tests at the power spectrum and parameter level.
We find excellent agreement between frequencies and spectrum types and our
results are robust to the modeling of astrophysical foregrounds. We report
results for CDM and a series of extensions, drawing on the following
parameters: the amplitude of the gravitational lensing effect on primary power
spectra , the effective number of neutrino species
, the primordial helium abundance , and the
baryon clumping factor due to primordial magnetic fields . We find that the
SPT-3G 2018 data are well fit by CDM with a
probability-to-exceed of . For CDM, we constrain the expansion
rate today to and the
combined structure growth parameter to . The SPT-based
results are effectively independent of Planck, and the cosmological parameter
constraints from either data set are within of each other.
(abridged)Comment: 35 Pages, 17 Figures, 11 Table
Flaring Stars in a Non-targeted mm-wave Survey with SPT-3G
We present a flare star catalog from four years of non-targeted
millimeter-wave survey data from the South Pole Telescope (SPT). The data were
taken with the SPT-3G camera and cover a 1500-square-degree region of the sky
from to in right ascension and
to in declination. This region was observed on a
nearly daily cadence from 2019-2022 and chosen to avoid the plane of the
galaxy. A short-duration transient search of this survey yields 111 flaring
events from 66 stars, increasing the number of both flaring events and detected
flare stars by an order of magnitude from the previous SPT-3G data release. We
provide cross-matching to Gaia DR3, as well as matches to X-ray point sources
found in the second ROSAT all-sky survey. We have detected flaring stars across
the main sequence, from early-type A stars to M dwarfs, as well as a large
population of evolved stars. These stars are mostly nearby, spanning 10 to 1000
parsecs in distance. Most of the flare spectral indices are constant or gently
rising as a function of frequency at 95/150/220 GHz. The timescale of these
events can range from minutes to hours, and the peak luminosities
range from to erg s in the SPT-3G frequency bands
NuSTAR and Chandra observations of new X-ray transients in the central parsec of the Galaxy
We report NuSTAR and Chandra observations of two X-ray transients, SWIFT
J174540.7290015 (T15) and SWIFT J174540.2290037 (T37), which were
discovered by the Neil Gehrels Swift Observatory in 2016 within pc of
Sgr A*. NuSTAR detected bright X-ray outbursts from T15 and T37, likely in the
soft and hard states, with 3-79~keV luminosities of and
erg/s, respectively. No X-ray outbursts have previously been
detected from the two transients and our Chandra ACIS analysis puts an upper
limit of erg/s on their quiescent 2-8 keV
luminosities. No pulsations, significant QPOs, or type I X-ray bursts were
detected in the NuSTAR data. While T15 exhibited no significant red noise, the
T37 power density spectra are well characterized by three Lorentzian
components. The declining variability of T37 above Hz is typical
of black hole (BH) transients in the hard state. NuSTAR spectra of both
transients exhibit a thermal disk blackbody, X-ray reflection with broadened Fe
atomic features, and a continuum component well described by Comptonization
models. Their X-ray reflection spectra are most consistent with high BH spin
() and large disk density ( cm).
Based on the best-fit ionization parameters and disk densities, we found that
X-ray reflection occurred near the inner disk radius, which was derived from
the relativistic broadening and thermal disk component. These X-ray
characteristics suggest the outbursting BH-LMXB scenario for both transients
and yield the first BH spin measurements from X-ray transients in the central
100 pc region.Comment: 15 pages, 7 figures, accepted for publication in Ap
A Measurement of Gravitational Lensing of the Cosmic Microwave Background Using SPT-3G 2018 Data
We present a measurement of gravitational lensing over 1500 deg of the
Southern sky using SPT-3G temperature data at 95 and 150 GHz taken in 2018. The
lensing amplitude relative to a fiducial Planck 2018 CDM cosmology is
found to be , excluding instrumental and astrophysical
systematic uncertainties. We conduct extensive systematic and null tests to
check the robustness of the lensing measurements, and report a minimum-variance
combined lensing power spectrum over angular multipoles of , which
we use to constrain cosmological models. When analyzed alone and jointly with
primary cosmic microwave background (CMB) spectra within the CDM
model, our lensing amplitude measurements are consistent with measurements from
SPT-SZ, SPTpol, ACT, and Planck. Incorporating loose priors on the baryon
density and other parameters including uncertainties on a foreground bias
template, we obtain a constraint on using the SPT-3G 2018 lensing data alone, where
is a common measure of the amplitude of structure today and
is the matter density parameter. Combining SPT-3G 2018 lensing
measurements with baryon acoustic oscillation (BAO) data, we derive parameter
constraints of , , and Hubble constant
km s Mpc. Using CMB anisotropy and lensing measurements from
SPT-3G only, we provide independent constraints on the spatial curvature of
(95% C.L.) and the dark energy density
of (68% C.L.). When combining SPT-3G
lensing data with SPT-3G CMB anisotropy and BAO data, we find an upper limit on
the sum of the neutrino masses of eV (95% C.L.)
Testing the ΛCDM cosmological model with forthcoming measurements of the cosmic microwave background with SPT-3G
We forecast constraints on cosmological parameters enabled by three surveys conducted with SPT-3G, the third-generation camera on the South Pole Telescope. The surveys cover separate regions of 1500, 2650, and 6000 deg2 to different depths, in total observing 25% of the sky. These regions will be measured to white noise levels of roughly 2.5, 9, and 12μK -armin, respectively, in cosmic microwave background (CMB) temperature units at 150 GHz by the end of 2024. The survey also includes measurements at 95 and 220 GHz, which have noise levels a factor of ∼1.2 and 3.5 times higher than 150 GHz, respectively, with each band having a polarization noise level ∼2 times higher than the temperature noise. We use a novel approach to obtain the covariance matrices for jointly and optimally estimated gravitational lensing potential band powers and unlensed CMB temperature and polarization band powers. We demonstrate the ability to test the ΛCDM model via the consistency of cosmological parameters constrained independently from SPT-3G and Planck data, and consider the improvement in constraints on ΛCDM extension parameters from a joint analysis of SPT-3G and Planck data. The ΛCDM cosmological parameters are typically constrained with uncertainties up to ∼2 times smaller with SPT-3G data, compared to Planck, with the two data sets measuring significantly different angular scales and polarization levels, providing additional tests of the standard cosmological model
Flaring stars in a nontargeted millimeter-wave survey with SPT-3G
We present a flare star catalog from 4 yr of nontargeted millimeter-wave survey data from the South Pole Telescope (SPT). The data were taken with the SPT-3G camera and cover a 1500 deg2 region of the sky from 20h40m0s to 3h20m0s in right ascension and from −42° to −70° in declination. This region was observed on a nearly daily cadence from 2019 to 2022 and chosen to avoid the plane of the galaxy. A short-duration transient search of this survey yields 111 flaring events from 66 stars, increasing the number of both flaring events and detected flare stars by an order of magnitude from the previous SPT-3G data release. We provide cross-matching to Gaia DR3, as well as matches to X-ray point sources found in the second ROSAT all-sky survey. We have detected flaring stars across the main sequence, from early-type A stars to M dwarfs, as well as a large population of evolved stars. These stars are mostly nearby, spanning 10–1000 pc in distance. Most of the flare spectral indices are constant or gently rising as a function of frequency at 95/150/220 GHz. The timescale of these events can range from minutes to hours, and the peak ν L ν luminosities range from 1027 to 1031 erg s−1 in the SPT-3G frequency bands
Mass calibration of DES Year-3 clusters via SPT-3G CMB cluster lensing
We measure the stacked lensing signal in the direction of galaxy clusters in the Dark Energy Survey Year 3 (DES Y3) redMaPPer sample, using cosmic microwave background (CMB) temperature data from SPT-3G, the third-generation CMB camera on the South Pole Telescope (SPT). Here, we estimate the lensing signal using temperature maps constructed from the initial 2 years of data from the SPT-3G 'Main' survey, covering 1500 deg2 of the Southern sky. We then use this lensing signal as a proxy for the mean cluster mass of the DES sample. The thermal Sunyaev-Zel'dovich (tSZ) signal, which can contaminate the lensing signal if not addressed, is isolated and removed from the data before obtaining the mass measurement. In this work, we employ three versions of the redMaPPer catalogue: a Flux-Limited sample containing 8865 clusters, a Volume-Limited sample with 5391 clusters, and a Volume&Redshift-Limited sample with 4450 clusters. For the three samples, we detect the CMB lensing signal at a significance of 12.4σ, 10.5σ and 10.2σ and find the mean cluster masses to be M 200m = 1.66±0.13 [stat.]± 0.03 [sys.], 1.97±0.18 [stat.]± 0.05 [sys.], and 2.11±0.20 [stat.]± 0.05 [sys.]×1014 M⊙, respectively. This is a factor of ∼ 2 improvement relative to the precision of measurements with previous generations of SPT surveys and the most constraining cluster mass measurements using CMB cluster lensing to date. Overall, we find no significant tensions between our results and masses given by redMaPPer mass-richness scaling relations of previous works, which were calibrated using CMB cluster lensing, optical weak lensing, and velocity dispersion measurements from various combinations of DES, SDSS and Planck data. We then divide our sample into 3 redshift and 3 richness bins, finding no significant discrepancies with optical weak-lensing calibrated masses in these bins. We forecast a 5.7% constraint on the mean cluster mass of the DES Y3 sample with the complete SPT-3G surveys when using both temperature and polarization data and including an additional ∼ 1400 deg2 of observations from the 'Extended' SPT-3G survey