20 research outputs found
Event horizon telescope observations of the jet launching and collimation in Centaurus A
Very-long-baseline interferometry (VLBI) observations of active galactic nuclei at millimetre wavelengths have the power to reveal the launching and initial collimation region of extragalactic radio jets, down to 10-100 gravitational radii (r_g ≡ GM/c^2) scales in nearby sources1. Centaurus A is the closest radio-loud source to Earth2. It bridges the gap in mass and accretion rate between the supermassive black holes (SMBHs) in Messier 87 and our Galactic Centre. A large southern declination of −43° has, however, prevented VLBI imaging of Centaurus A below a wavelength of 1 cm thus far. Here we show the millimetre VLBI image of the source, which we obtained with the Event Horizon Telescope at 228 GHz. Compared with previous observations3, we image the jet of Centaurus A at a tenfold higher frequency and sixteen times sharper resolution and thereby probe sub-lightday structures. We reveal a highly collimated, asymmetrically edge-brightened jet as well as the fainter counterjet. We find that the source structure of Centaurus A resembles the jet in Messier 87 on ~500 r_g scales remarkably well. Furthermore, we identify the location of Centaurus A's SMBH with respect to its resolved jet core at a wavelength of 1.3 mm and conclude that the source's event horizon shadow4 should be visible at terahertz frequencies. This location further supports the universal scale invariance of black holes over a wide range of masses^5,6.https://www.nature.com/articles/s41550-021-01417-
Event Horizon Telescope observations of the jet launching and collimation in Centaurus A
Very-long-baseline interferometry (VLBI) observations of active galactic nuclei at millimetre wavelengths have the power to reveal the launching and initial collimation region of extragalactic radio jets, down to 10–100 gravitational radii (rg ≡ GM/c2) scales in nearby sources. Centaurus A is the closest radio-loud source to Earth2. It bridges the gap in mass and accretion rate between the supermassive black holes (SMBHs) in Messier 87 and our Galactic Centre. A large southern declination of −43° has, however, prevented VLBI imaging of Centaurus A below a wavelength of 1 cm thus far. Here we show the millimetre VLBI image of the source, which we obtained with the Event Horizon Telescope at 228 GHz. Compared with previous observations, we image the jet of Centaurus A at a tenfold higher frequency and sixteen times sharper resolution and thereby probe sub-lightday structures. We reveal a highly collimated, asymmetrically edge-brightened jet as well as the fainter counterjet. We find that the source structure of Centaurus A resembles the jet in Messier 87 on ~500 rg scales remarkably well. Furthermore, we identify the location of Centaurus A’s SMBH with respect to its resolved jet core at a wavelength of 1.3 mm and conclude that the source’s event horizon shadow should be visible at terahertz frequencies. This location further supports the universal scale invariance of black holes over a wide range of masses.A.C. is an Einstein Fellow of the NASA Hubble Fellowship Program. J.P is an EACOA
fellow. Z.Y. is a UKRI Stephen Hawking Fellow. We thank the following organizations
and programmes: the Academy of Finland (projects 274477, 284495, 312496, 315721);
the Agencia Nacional de Investigación y Desarrollo (ANID), Chile via NCN19_058
(TITANs) and Fondecyt 3190878; the Alexander von Humboldt Stiftung; an Alfred P.
Sloan Research Fellowship; Allegro, the European ALMA Regional Centre node in the
Netherlands, the NL astronomy research network NOVA and the astronomy institutes
of the University of Amsterdam, Leiden University and Radboud University; the Black
Hole Initiative at Harvard University, through a grant (60477) from the John Templeton
Foundation; the China Scholarship Council; Consejo Nacional de Ciencia y Tecnología
(CONACYT, Mexico, projects U0004-246083, U0004-259839, F0003-272050, M0037-
279006, F0003-281692, 104497, 275201, 263356, 57265507); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Dirección General
de Asuntos del Personal Académico-Universidad Nacional Autónoma de México
(DGAPA-UNAM, projects IN112417 and IN112820); the EACOA Fellowship of the
East Asia Core Observatories Association; the European Research Council Synergy
Grant “BlackHoleCam: Imaging the Event Horizon of Black Holes” (grant 610058);
the Generalitat Valenciana postdoctoral grant APOSTD/2018/177 and GenT Program
(project CIDEGENT/2018/021); MICINN Research Project PID2019-108995GB-C22;
the Gordon and Betty Moore Foundation (grants GBMF- 3561, GBMF-5278); the
Istituto Nazionale di Fisica Nucleare (INFN) sezione di Napoli, iniziative specifiche
TEONGRAV; the International Max Planck Research School for Astronomy and
Astrophysics at the Universities of Bonn and Cologne; Joint Princeton/Flatiron and
Joint Columbia/Flatiron Postdoctoral Fellowships, research at the Flatiron Institute is
supported by the Simons Foundation; the Japanese Government (Monbukagakusho:
MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid
for JSPS Research Fellowship (JP17J08829); the Key Research Program of Frontier
Sciences, Chinese Academy of Sciences (CAS, grants QYZDJ-SSW-SLH057, QYZDJSSWSYS008,
ZDBS-LY-SLH011).
We further thank the Leverhulme Trust Early Career Research Fellowship; the
Max-Planck-Gesellschaft (MPG); the Max Planck Partner Group of the MPG and
the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP18K13594, JP18K03656,
JP18H03721, 18K03709, 18H01245, JP19H01943, 25120007); the Malaysian
Fundamental Research Grant Scheme (FRGS) FRGS/1/2019/STG02/UM/02/6; the
MIT International Science and Technology Initiatives (MISTI) Funds; the Ministry
of Science and Technology (MOST) of Taiwan (105- 2112-M-001-025-MY3, 106-
2112-M-001-011, 106-2119- M-001-027, 107-2119-M-001-017, 107-2119-M-001- 020, 107-2119-M-110-005, 108-2112-M-001-048, and 109-2124-M-001-005); the
National Aeronautics and Space Administration (NASA, Fermi Guest Investigator
grant 80NSSC20K1567, NASA Astrophysics Theory Program grant 80NSSC20K0527,
NASA grant NNX17AL82G, and Hubble Fellowship grant HST-HF2-51431.001-A
awarded by the Space Telescope Science Institute, which is operated by the Association
of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-
26555, and NASA NuSTAR award 80NSSC20K0645); the National Institute of Natural
Sciences (NINS) of Japan; the National Key Research and Development Program of
China (grant 2016YFA0400704, 2016YFA0400702); the National Science Foundation
(NSF, grants AST-0096454, AST-0352953, AST-0521233, AST-0705062, AST-0905844,
AST-0922984, AST-1126433, AST-1140030, DGE-1144085, AST-1207704, AST-
1207730, AST-1207752, MRI-1228509, OPP-1248097, AST-1310896, AST-1337663,
AST-1440254, AST-1555365, AST-1615796, AST-1715061, AST-1716327, AST-
1716536, OISE-1743747, AST-1816420, AST-1903847, AST-1935980, AST-2034306);
the Natural Science Foundation of China (grants 11573051, 11633006, 11650110427,
10625314, 11721303, 11725312, 11933007, 11991052, 11991053); a fellowship of
China Postdoctoral Science Foundation (2020M671266); the Natural Sciences and
Engineering Research Council of Canada (NSERC, including a Discovery Grant and
the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program);
the National Research Foundation of Korea (the Global PhD Fellowship Grant: grants
2014H1A2A1018695, NRF-2015H1A2A1033752, 2015- R1D1A1A01056807, the Korea
Research Fellowship Program: NRF-2015H1D3A1066561, Basic Research Support Grant
2019R1F1A1059721); the Netherlands Organization for Scientific Research (NWO)
VICI award (grant 639.043.513) and Spinoza Prize SPI 78-409; the New Scientific
Frontiers with Precision Radio Interferometry Fellowship awarded by the South African
Radio Astronomy Observatory (SARAO), which is a facility of the National Research
Foundation (NRF), an agency of the Department of Science and Innovation (DSI) of
South Africa; the South African Research Chairs Initiative of the Department of Science
and Innovation and National Research Foundation; the Onsala Space Observatory
(OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017-
00648) the Perimeter Institute for Theoretical Physics (research at Perimeter Institute
is supported by the Government of Canada through the Department of Innovation,
Science and Economic Development and by the Province of Ontario through the
Ministry of Research, Innovation and Science); the Spanish Ministerio de Economía
y Competitividad (grants PGC2018-098915-B-C21, AYA2016-80889-P, PID2019-
108995GB-C21); the State Agency for Research of the Spanish MCIU through the ‘Center
of Excellence Severo Ochoa’ award for the Instituto de Astrofísica de Andalucía (SEV-
2017- 0709); the Toray Science Foundation; the Consejería de Economía, Conocimiento,
Empresas y Universidad of the Junta de Andalucía (grant P18-FR-1769), the Consejo
Superior de Investigaciones Científicas (grant 2019AEP112); the US Department of
Energy (US DOE) through the Los Alamos National Laboratory (operated by Triad
National Security, LLC, for the National Nuclear Security Administration of the US
DOE (Contract 89233218CNA000001); the European Union’s Horizon 2020 research
and innovation programme under grant agreement No 730562 RadioNet; ALMA North
America Development Fund; the Academia Sinica; Chandra TM6- 17006X and DD7-
18089X; the GenT Program (Generalitat Valenciana) Project CIDEGENT/2018/021.
This work used the Extreme Science and Engineering Discovery Environment
(XSEDE), supported by NSF grant ACI-1548562, and CyVerse, supported by NSF grants
DBI-0735191, DBI-1265383, and DBI-1743442. XSEDE Stampede2 resource at TACC
was allocated through TG-AST170024 and TG-AST080026N. XSEDE JetStream resource
at PTI and TACC was allocated through AST170028. The simulations were performed
in part on the SuperMUC cluster at the LRZ in Garching, on the LOEWE cluster in
CSC in Frankfurt, and on the HazelHen cluster at the HLRS in Stuttgart. This research was enabled in part by support provided by Compute Ontario (http://computeontario.
ca), Calcul Quebec (http://www.calculquebec.ca) and Compute Canada (http://www.
computecanada.ca). We thank the staff at the participating observatories, correlation
centres, and institutions for their enthusiastic support.
This paper makes use of the following ALMA data: ADS/JAO.ALMA#2016.1.01198.V.
ALMA is a partnership of the European Southern Observatory (ESO; Europe,
representing its member states), NSF, and National Institutes of Natural Sciences of Japan,
together with National Research Council (Canada), Ministry of Science and Technology
(MOST; Taiwan), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA;
Taiwan), and Korea Astronomy and Space Science Institute (KASI; Republic of Korea), in
cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO,
Associated Universities, Inc. (AUI)/NRAO, and the National Astronomical Observatory of
Japan (NAOJ). The NRAO is a facility of the NSF operated under cooperative agreement
by AUI. APEX is a collaboration between the Max-Planck-Institut für Radioastronomie
(Germany), ESO, and the Onsala Space Observatory (Sweden). The SMA is a joint project
between the SAO and ASIAA and is funded by the Smithsonian Institution and the
Academia Sinica. The JCMT is operated by the East Asian Observatory on behalf of the
NAOJ, ASIAA, and KASI, as well as the Ministry of Finance of China, Chinese Academy
of Sciences, and the National Key R&D Program (No. 2017YFA0402700) of China.
Additional funding support for the JCMT is provided by the Science and Technologies
Facility Council (UK) and participating universities in the UK and Canada. The LMT is a
project operated by the Instituto Nacional de Astrófisica, Óptica, y Electrónica (Mexico)
and the University of Massachusetts at Amherst (USA), with financial support from
the Consejo Nacional de Ciencia y Tecnología and the National Science Foundation.
The IRAM 30-m telescope on Pico Veleta, Spain is operated by IRAM and supported
by CNRS (Centre National de la Recherche Scientifique, France), MPG (Max-Planck-
Gesellschaft, Germany) and IGN (Instituto Geográfico Nacional, Spain). The SMT is
operated by the Arizona Radio Observatory, a part of the Steward Observatory of the
University of Arizona, with financial support of operations from the State of Arizona and
financial support for instrumentation development from the NSF. The SPT is supported
by the National Science Foundation through grant PLR- 1248097. Partial support is also
provided by the NSF Physics Frontier Center grant PHY-1125897 to the Kavli Institute of
Cosmological Physics at the University of Chicago, the Kavli Foundation and the Gordon
and Betty Moore Foundation grant GBMF 947. The SPT hydrogen maser was provided
on loan from the GLT, courtesy of ASIAA. The EHTC has received generous donations
of FPGA chips from Xilinx Inc., under the Xilinx University Program. The EHTC has benefited from technology shared under open-source license by the Collaboration for
Astronomy Signal Processing and Electronics Research (CASPER). The EHT project is
grateful to T4Science and Microsemi for their assistance with Hydrogen Masers. This
research has made use of NASA’s Astrophysics Data System. We gratefully acknowledge
the support provided by the extended staff of the ALMA, both from the inception of the
ALMA Phasing Project through the observational campaigns of 2017 and 2018. We would
like to thank A. Deller and W. Brisken for EHT-specific support with the use of DiFX. We
acknowledge the significance that Maunakea, where the SMA and JCMT EHT stations are
located, has for the indigenous Hawaiian people.
The grants listed above collectively fund the Event Horizon Telescope project.http://www.nature.com/natureastronomyam2023Physic
Event Horizon Telescope observations of the jet launching and collimation in Centaurus A
Abstract: Very-long-baseline interferometry (VLBI) observations of active galactic nuclei at millimetre wavelengths have the power to reveal the launching and initial collimation region of extragalactic radio jets, down to 10–100 gravitational radii (rg ≡ GM/c2) scales in nearby sources1. Centaurus A is the closest radio-loud source to Earth2. It bridges the gap in mass and accretion rate between the supermassive black holes (SMBHs) in Messier 87 and our Galactic Centre. A large southern declination of −43° has, however, prevented VLBI imaging of Centaurus A below a wavelength of 1 cm thus far. Here we show the millimetre VLBI image of the source, which we obtained with the Event Horizon Telescope at 228 GHz. Compared with previous observations3, we image the jet of Centaurus A at a tenfold higher frequency and sixteen times sharper resolution and thereby probe sub-lightday structures. We reveal a highly collimated, asymmetrically edge-brightened jet as well as the fainter counterjet. We find that the source structure of Centaurus A resembles the jet in Messier 87 on ~500 rg scales remarkably well. Furthermore, we identify the location of Centaurus A’s SMBH with respect to its resolved jet core at a wavelength of 1.3 mm and conclude that the source’s event horizon shadow4 should be visible at terahertz frequencies. This location further supports the universal scale invariance of black holes over a wide range of masses5, 6
Changes in EEG power density of NREM sleep in depressed patients during treatment with citalopram
According to a recent hypothesis the therapeutic effects of antidepressants might be related to acute or cumulative suppression of NREM sleep intensity. This intensity has been proposed to be expressed in the EEG power density in NREM sleep. In the present study the relationship was examined between the changes of EEG power density in NREM sleep and the changes in clinical state in 16 depressed patients during treatment with citalopram, a highly specific serotonin uptake inhibitor. A one-week wash-out period was followed by 1 week of placebo administration, a medication period of 5 weeks, and a one-week placebo period. In order to minimize systematic influences of sleep duration and NREM-REM sleep alterations, EEG power was measured over the longest common amount of NREM sleep stages 2, 3 and 4 (91.5 min). During the last treatment week and the week after withdrawal, a significant decrease of EEG power as compared to baseline was found in the 8-9 Hz frequency range. No clear-cut change, however, was observed in the EEG power of the delta frequency range (1-4 Hz), which is considered to be the principle manifestation of NREMS intensity. Furthermore, no relationship between changes in EEG power density and changes in clinical state could be demonstrated.
Changes in EEG power density of non-REM sleep in depressed patients during treatment with trazodone
Recently, it was hypothesized that acute or cumulative suppression of non-REM sleep intensity might be related to the therapeutic effects of antidepressants. This intensity has been proposed to be expressed in the EEG power density in non-REM sleep. In the present study, the relationship was examined between the changes of EEG power density in non-REM sleep and the changes in clinical state in 8 depressed patients during treatment with trazodone. A 1-week wash-out period was followed by 1 week of placebo administration, a medication period of 5 weeks and a 1-week placebo period. To minimize systematic influences of sleep duration and non-REM-REM sleep alterations, EEG power was measured over the longest common amount of non-REM sleep stages 2-4 (168.5 min), accumulated from sleep onset onwards. During trazodone treatment, the 13-and 14-Hz bins showed a significant reduction in EEG power. No clear-cut change, however, was observed in the EEG power of the δ frequency range (1-4 Hz) which is considered to be the principle manifestation of non-REM sleep intensity. Furthermore, no overall significant relationship between EEG power suppression and clinical improvement could be demonstrated.
Changes in sleep polygraphic variables and clinical state in depressed patients during treatment with citalopram
Drug-induced improvement of depression may be mediated by changes in sleep physiology. The aim of this study was to relate changes in sleep polygraphic variables to clinical state during treatment with citalopram, a highly specific serotonin uptake inhibitor. Sixteen patients took part. The study was single-blind and uncontrolled. A 1-week wash-out period was followed by 1 week of placebo administration, a medication period of 5 weeks, and a 1-week placebo period. For the entire group a significant decrease of rapid eye movement sleep (REMS) and a significant lengthening of REMS latency were observed initially as well as at the end of treatment. No changes in sleep continuity were found, but non-REMS stage 2 (percentage) was significantly increased. On the basis of clinical change, as expressed by the scores of the Hamilton Rating Scale for Depression, at the end of the citalopram treatment the patient group was split in two halves: eight less and eight more improved patients. The groups did not differ with respect to any sleep polygraphic variable.
A therapeutic application of the experience sampling method in the treatment of depression: a randomized controlled trial
In depression, the ability to experience daily life positive affect predicts recovery and reduces relapse rates. Interventions based on the experience sampling method (ESM-I) are ideally suited to provide insight in personal, contextualized patterns of positive affect. The aim of this study was to examine whether add-on ESM-derived feedback on personalized patterns of positive affect is feasible and useful to patients, and results in a reduction of depressive symptomatology. Depressed outpatients (n=102) receiving pharmacological treatment participated in a randomized controlled trial with three arms: an experimental group receiving add-on ESM-derived feedback, a pseudo-experimental group participating in ESM but receiving no feedback, and a control group. The experimental group participated in an ESM procedure (three days per week over a 6-week period) using a palmtop. This group received weekly standardized feedback on personalized patterns of positive affect. Hamilton Depression Rating Scale - 17 (HDRS) and Inventory of Depressive Symptoms (IDS) scores were obtained before and after the intervention. During a 6-month follow-up period, five HDRS and IDS assessments were completed. Add-on ESM-derived feedback resulted in a significant and clinically relevant stronger decrease in HDRS score relative to the control group (p<0.01; -5.5 point reduction in HDRS at 6 months). Compared to the pseudo-experimental group, a clinically relevant decrease in HDRS score was apparent at 6 months (B=-3.6, p=0.053). Self-reported depressive complaints (IDS) yielded the same pattern over time. The use of ESM-I was deemed acceptable and the provided feedback easy to understand. Patients attempted to apply suggestions from ESM-derived feedback to daily life. These data suggest that the efficacy of traditional passive pharmacological approach to treatment of major depression can be enhanced by using person-tailored daily life information regarding positive affect.status: publishe
Experience sampling-based personalized feedback and positive affect: a randomized controlled trial in depressed patients
Positive affect (PA) plays a crucial role in the development, course, and recovery of depression. Recently, we showed that a therapeutic application of the experience sampling method (ESM), consisting of feedback focusing on PA in daily life, was associated with a decrease in depressive symptoms. The present study investigated whether the experience of PA increased during the course of this intervention.status: publishe