adsabs/WIESP2022-NER huggingface dataset:
Paper: 2021MNRAS.503..426H (fulltext)
the strongest deviations growing at the particle Nyquist wavenumber k Ny (indicated by a dotted vertical line) – and linear perturbation theory is not recovered even on the largest scales. While we show results only for 1LPT and at starting time z start = 49, this result is almost independent of the used LPT order. Since the error is driven by a spurious growing mode, its amplitude is to first order simply determined by the starting time – with earlier starts leading to a larger error. It is also insensitive to the specific choice of softening length, as long as it is appreciably smaller than the mean particle separations. Once the small scales have shell-crossed and collapsed, at z ≲ 2.5, the spurious growth is slowed. Figure 6. Evolution of the baryon–CDM density difference power spectrum P bc in a gravity-only N -body simulations, where both baryon and CDM are simulated with N -body particles with small softening. Simulation results in solid lines (faint dashed lines) with 2 × 512 3 (2 × 1024 3 ) particles initialized at z start = 49 ( z start = 24) using 1LPT (3LPT) ICs, by suitably backscaling the amplitudes from Class at the reference redshift z ref = 2.125. Those backscaled power spectra are shown as black dashed lines, before applying the particle realization. The vertical dotted line indicates the particle Nyquist wavenumber. Top panel: Simulation results where is absorbed into particle displacements (using equation 14 ). We observe the well-known spurious growing mode due to discreteness errors in the particle discretization of the fluids (the discrete δ bc is not compensated at the discretization scale, if not sufficiently smoothed by gravitational softening, and therefore grows). Bottom panel: Same as above but now is absorbed into perturbed particle masses (using equation 15 ). Here, discretization errors are strongly suppressed, and the late-time power asymptotes to a constant noise spectrum beyond k Ny . These errors are furthermore vastly reduced when 2 × 1024 3 particles and 3LPT ICs are used. In stark contrast, the situation improves dramatically when the initial density perturbation is incorporated by perturbing the initial particle masses (using equation 15 ), instead of adding initial displacements. This result is shown in the lower panel of Fig. 6 in solid lines with the same particle load and resolution as above, while the results from the higher resolution simulation (2 × 1024 3 particles, 3LPT with z start = 24) are shown as faint dashed lines. In this case, P bc is exactly constant on large scales and exhibits non-linear growth at intermediate scales, as expected. On the smallest scales, we observe that in all cases the solution asymptotes to a constant power spectrum for k ≳ k Ny with a scaling inversely proportional to the particle number (as is expected for shot noise in the power spectrum, e.g. Colombi et al. 2009 ). We expect that this behaviour close to the particle Nyquist wavenumber is thus a combination of
Paper: 2019ApJ...879....8S (fulltext)
comprehensive data on jet motions come from studies of the nearest sources, particularly the Fanaroff–Riley type-I (FR I; Fanaroff Riley 1974 ) radio galaxies M87 (Reid et al. 1989 ; Biretta et al. 1995 ; Cheung et al. 2007 ; Kovalev et al. 2007 ) and Centaurus A (Goodger et al. 2010 ; Müller et al. 2014 ). M87 is a nearby source, at a distance of only 16.7 Mpc (Blakeslee et al. 2009 ), that hosts a bright jet spanning 20′′, ∼1.6 kpc projected, from the central AGN of the system. Kiloparsec-scale, knotted structure has been directly observed within the jet using radio, optical, and X-ray observations (e.g., Owen et al. 1989 ; Sparks et al. 1996 ; Harris et al. 1997 ; Perlman et al. 2001 ; Marshall et al. 2002 ; Perlman Wilson 2005 ; Meyer et al. 2013 ). Previous measurements of proper motions in M87 have detected sub-relativistic speeds within a parsec of the AGN using the Very Long Baseline Interferometry (VLBI; Reid et al. 1989 ; Kovalev et al. 2007 ; Mertens et al. 2016 ; Walker et al. 2018 ). Superluminal motions on larger-scales were detected from the VLBI (Cheung et al. 2007 ; Giroletti et al. 2012 ), the Very Large Array (VLA; Biretta et al. 1995 ), and the Hubble Space Telescope ( HST ; Biretta et al. 1999 ; Meyer et al. 2013 ). While proper motions have yet to be detected at higher energies, measuring the kinematics of X-ray-emitting regions potentially provides the best probe for sites of particle acceleration because high energy radiation is produced by more energetic particles. Recent work from Snios et al. ( 2019 ) measured X-ray proper motions for the first time in the jet of Centaurus A, at a distance of 3.8 Mpc (Harris et al. 2010 ), by applying new methods to analyze Chandra observations. We may apply those techniques to measure proper motions in the X-ray jet of M87. In this work, we investigate proper motions and brightness variations within the X-ray jet of M87 using two Chandra observations separated by 5 yr. The remainder of the paper is structured as follows. Section 2 discusses the details of the Chandra observations and the corresponding data reduction. In Section 3 , difference maps are generated from the coaligned observations and statistical uncertainties are quantified. Evidence of proper motion for the innermost knots of the X-ray jet are presented in Section 4 . In Section 5 , the proper motion results are compared with measurements from other wavelengths. Lastly, brightness changes of the knots are utilized to investigate both the primary mechanism for fading and the magnetic field strengths of the knots. 2. Data Acquisition and Reduction The jet of M87 is known to be a bright X-ray source. In existing Chandra observations with the Advanced CCD Imaging Spectrometer (ACIS), several features of the jet, including the AGN and HST-1, are significantly affected by pile-up (>0.25 counts frame −1 ; Marshall et al. 2002 ; Wilson Yang 2002 ; Harris et al. 2003 ). ACIS observations were initially considered for our
Paper: 2018MNRAS.479L..12E (fulltext)
r in = 0.1, and magnetic dipole moment μ 26 = 0.5. It is seen that the model can produce the values measured in the RMSP and LMXB states, consistently with the observed X-ray luminosities. The in the LMXB state is about six times greater than that in the RMSP state. This changes r in only by a small factor of ∼1.09 due to very weak dependence of r in on . The resultant increase in the spin-down torque is also small (∼27 per cent) in good agreement with the observations. Since the accretion and dipole torques are only a few per cent of the torque produced by the disc–field interaction, the onset of accretion with the transition to the weak-propeller phase does not affect significantly. With μ 26 = 4.7, estimated in our model, the dipole torque is found to be about five and seven times smaller than the observed torques in the RMSP and LMXB states, respectively. We note that for r in scaling with r A in the propeller phase, the magnetic torque would be proportional to , implying changes by a factor of ∼5, not in agreement with the measured torques. Table 1. The model parameters and results for J1023. These results are obtained with η = 0.78, Δ r / r in = 0.1, and magnetic dipole moment μ 26 = 0.5. The L x, model values for the high mode and the low mode correspond to L * and L d , respectively. In the last column, Γ acc and Γ tot are the magnitudes of the accretion (spin-up) and the spin-down torques, respectively. For the RMSP state, the observed L x ∼ 10 32 erg s −1 given in Table 1 is the 0.5–10 keV luminosity estimated by Archibald et al. ( 2010 ). From the spectral fits, Li et al. ( 2014 ) estimated that the 3–79 keV luminosity is 5 × 10 32 erg s −1 . In both observations, the X-ray flux was found to be modulated with the orbital motion, which is likely to be due to an intra-binary shock produced by the interaction of pulsar wind with the matter outflowing from the companion. A shock region close to the inner Lagrangian point that is eclipsed when the companion star is between the Earth and the neutron star could explain the observed modulations (Archibald et al. 2010 ; Bogdanov et al. 2011 ; see also Li et al. 2014 for a different interpretation). From the orbital modulations, it is expected that at least half of the X-rays are produced at the shock region in the RMSP state. These observations do not exclude a continuous emission from the disc with r in close to r co characterized by the conditions around the inner disc in the RMSP state. A large fraction of the total L x is emitted by the intra-binary shock modulated by the orbital motion, while the remaining smaller fraction could be produced by the inner disc. The X-ray luminosity estimated in our model is compatible with (smaller than) the continuous portion of the total X-ray luminosity in the RMSP state. We note that the disc emission spectrum could significantly change in the RMSP state due to strong propeller mechanism which can produce not only mass outflow but also hot matter
Paper: 2020MNRAS.492..934B (acknowledgments)
ACKNOWLEDGEMENTS Development of the robotic SL-SLODAR was funded by the European Southern Observatory (ESO). The authors would like to thank the staff at Paranal Observatory for their assistance with the robotic SL-SLODAR project. TB, JO, and RWW are grateful to the Science and Technology Facilities Committee (STFC) for financial support (grant reference ST/P000541/1). The authors would like to thank the anonymous reviewer for their constructive comments that helped to improve the paper. This research made use of python including numpy, scipy , (van der Walt, Colbert Varoquaux 2011 ) and matplotlib (Hunter 2007 ).
Paper: 2019MNRAS.490..600D (acknowledgments)
ACKNOWLEDGEMENTS We thank the anonymous referee for comments on the manuscript. GL acknowledges support from the European Union’s Horizon 2020 Sundial Innovative Training Network, grant no. 721463. This work has made use of the HyperLeda data base (Paturel et al. 2003 ).
Paper: 2017ApJ...840...66G (fulltext)
binaries, CVs, and qLMXBs in the comparison samples. The RS stars also fall in the same region as the SSGs. This overlap with the active binaries hints that heightened chromospheric activity may be responsible for the X-ray activity observed for at least some, and perhaps many, SSG and RS stars. The diminished overlap between the SSG and BY Dra stars (which are also chromospherically active) is due to the generally lower optical luminosities of most BY Dra stars in the comparison samples relative to the SSGs. The X-ray luminosities of the SSGs agree well with both the BY Dra and RS CVn active binary samples. 5.3. Frequency of SSGs across Different Star Clusters Figure 7 shows the number (top panel) and specific frequency (bottom panel) of SSGs as a function of the cluster mass for all clusters with SSGs in our sample. The black symbols in this figure show only the SSGs that are the most probable cluster members and are within our minimum radius completeness limit, and the gray symbols show all SSGs. The Pearson’s correlation coefficient, relating cluster mass and number of SSGs, for the full sample of highly likely cluster members is 0.925. However, this value is large because of ω Cen and 47 Tuc. Excluding these two clusters (the only ones in our sample with masses above 10 6 ) results in a Pearson’s correlation coefficient of −0.278. Furthermore, a test indicates that this limited sample of clusters (still excluding ω Cen and 47 Tuc) is consistent with a flat line at the mean value of SSGs. This result holds even if we include ω Cen and 47 Tuc in this test (using ), with a reduced value of . We conclude that, for this sample, there is no significant correlation between the number of SSGs and the cluster mass. This lack of a correlation in versus results in a clearly visible trend in the bottom panel of Figure 7 : the number of SSGs per unit mass increases toward lower-mass clusters. A test shows that the full sample of SSGs is inconsistent with a flat line at the mean value at very high significance (). The same result holds true for the open and globular clusters individually. The open clusters have a significantly higher specific frequency of SSGs than do the globular clusters. If we take the mean specific SSG frequency for the open clusters of ∼10 −3 −1 and extrapolate that to the globular cluster regime, this would predict about 100 SSGs in a globular cluster with a total mass of 10 5 . The maximum number of SSGs known in any cluster is 19 in ω Cen, followed by eight in 47 Tuc (both of which have masses ). A hint of this trend was also noted by Cool et al. ( 2013 ) in comparing their ω Cen SSG sample to those in M67 and NGC 6791. This is now verified with the larger sample of SSGs studied here, and we discuss the implications of this result in Section 6 . 5.4. Summary of Demographics We conclude that the SSG region has an elevated frequency of variable stars and X-ray sources relative to stars of similar luminosities in the normal
Paper: 2017A&A...608A..84C (acknowledgments)
We acknowledge valuable comments from an anonymous referee. L.C. and R.C. are supported by YDUN grant DFF 4090-00079. S.D.V. is supported by the French National Research Agency (ANR) under contract ANR-16-CE31-0003 BEaPro. S.L. has been supported by FONDECYT grant number 1140838 and partially by PFB-06 CATA. A.d.U.P. and C.T. acknowledge support from Ramón y Cajal fellowships, and with RSR a BBVA Foundation Grant for Researchers and Cultural Creators, and the Spanish Ministry of Economy and Competitiveness through project AYA2014-58381-P. G.B. acknowledges support from the National Science Foundation through grant AST-1615814. Z.C. acknowledges support from the Juan de la Cierva Incorporación fellowship IJCI-2014-21669 and from the Spanish research project AYA 2014-58381-P. P.J. and K.E.H. acknowledge support by a Project Grant (162948–051) from The Icelandic Research Fund. J.J. acknowledges support from NOVA and NWO-FAPESP grant for advanced instrumentation in astronomy. R.S.R. acknowledges support from ASI (Italian Space Agency) through the Contract No. 2015-046-R.0 and from European Union Horizon 2020 Programme under the AHEAD project (grant agreement No. 654215). M.V. gratefully acknowledges financial support from the Danish Council for Independent Research via grant no. DFF 4002-00275.
Paper: 2015A&A...576A..43F (acknowledgments)
We acknowledge L. Fuhrmann for careful reading and for useful comments and suggestions to the manuscript. We thank the anonymous referee for comments and criticism that helped to improve this manuscript. C.M.F. was supported for this research through a stipend from the International Max Planck Research School (IMPRS) for Astronomy and Astrophysics at the Universities of Bonn and Cologne. Part of this work was supported by the COST Action MP0905 “Black Holes in a violent Universe”. E.R. acknowledges partial support from MINECO grants AYA2009-13036-C02-02 and AYA2012-38491-C02-01 as well as Generalitat Valenciana grant PROMETEO/2009/104. M.P. acknowledges financial support from MINECO grants AYA2010-21322-C03-01, AYA2010-21097-C03-01, and CONSOLIDER2007-00050. This work is based on observations with the VLBA, which is operated by the NRAO, a facility of the NSF under cooperative agreement by Associated Universities Inc. This research made use of data from the MOJAVE database that is maintained by the MOJAVE team ( Lister et al. 2009 ).
Paper: 2019ApJ...878....8R (acknowledgments)
We thank Andy Strong, Regina Caputo, and an anonymous referee for a detailed reading of this paper and for several valuable suggestions. This work was supported by NSF grant AST-1263034, “REU Site: Astronomical Research and Instrumentation at Texas AM University.” We acknowledge support from NASA Astrophysics Theory grant NNX12AC71G. Work at NRL is supported by NASA. The Fermi -LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat à l’Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d’Études Spatiales in France. This work performed in part under DOE Contract DE-AC02-76SF00515. Software: Astropy (Astropy Collaboration et al. 2013 , 2018 ), Jupyter (Kluyver et al. 2016 ), Matplotlib (Hunter 2007 ), NumPy (van der Walt et al. 2011 ), Pandas (McKinney 2010 ), SciPy (Jones et al. 2001 ).
Paper: 2017ApJ...838...43K (acknowledgments)
We acknowledge the support of the U.S. National Science Foundation (NSF) for WHAM development, operations, and science activities. The survey observations and work presented here were funded by NSF awards AST-0607512 and AST-1108911. R.A.B. acknowledges support from the NASA grants NNX10AI70G and HST -GO-13721.001-A. A.S.H. acknowledges support from NASA grant HST -AR-14297.001-A. We would also like to acknowledge the support of NSF REU Site grant AST-1004881 and the contributions of undergraduate researchers Peter Doze (Texas Southern University), Andrew Eagon (University of Wisconsin-Whitewater), and Alex Orchard (University of Wisconsin-Madison) to the initial analysis of the WHAM all-sky survey results.
Paper: 2015ApJ...808..147N (acknowledgments)
E.N. thanks the staff of the Department of Astronomy of the University of Guanajuato for the continuous support during the development of this work.
Paper: 2015MNRAS.446.1268C (acknowledgments)
We thank the referee for very useful comments. We are grateful for support from the National Natural Science Foundation of China through grants 11373010 and 11473037.
Paper: 2017MNRAS.469.3405B (acknowledgments)
Acknowledgments This work is based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência e Tecnologia (Brazil) and south-eastCYT (Argentina). CB thanks to CNPq for financial support. RAR. acknowledges support from FAPERGS (project N0. 2366-2551/14-0) and CNPq (project N0. 470090/2013-8 and 302683/2013-5). This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. We acknowledge the usage of the HyperLeda database ( http://leda.univ-lyon1.fr ).
Paper: 2018ApJ...855...51S (fulltext)
and, instead, seem to confirm the action of a predominantly “high-soft” radiation field. 9. Dust and molecular gas-to-stellar mass ratios that are typically much higher than can be explained by stellar recycling from the aging burst population. This indicates that the dust and gas reservoirs were not entirely expelled during burst truncation. 10. Negative trends of PAH/TIR and dust-to-stellar mass ratio as a function of post-burst age, consistent with observations of dusty ETGs, indicating the effect of accumulating grain destruction and an incipient transition to virialized early-type gas conditions. 11. Little evidence for significant AGN activity beyond potential low-level activity associated with their existing LINER classifications. The high-ionization emission line [O iv ] is only detected in one source (weakly), and PAH band ratios show no evidence of small-grain depletion. One galaxy (2360_167_53728) displays extreme AGN colors in the near-IR WISE bands, with evidence for a very hot dust component to its SED. The presumed AGN is likely deeply embedded. Three sources appear to display an excess at 1.4 GHz, relative to the radio–infrared correlation, potentially indicating the presence of radio AGN activity. One source, in particular, is clearly a radio galaxy—the same source that is detected in [O iv ]. 12. Low star formation rates and efficiencies. Offsets from the star-forming main sequence are typically >10 and reach factors of >100 in some cases, for a variety of tracers, characterizing these galaxies as truly quiescent. Offsets from the KS relation exist for most sources and range from ∼3 to >10 for reliable tracers, depending on the comparison sample considered. These results paint a compelling picture: one of galaxies whose star formation was, indeed, rapidly truncated, and which are transitioning away from compact starbursting systems, but in which the gas and dust have not been completely expelled and instead are supported against further star formation by turbulent or mechanical heating. The resulting dense, modestly aged burst stellar populations appear to provide a “high-soft” radiation field, which dominates the unusual ISM energetics of galaxies seen after the fall from a prior star-forming peak. Appendix A Photometric Tables and SDSS Spectra In Tables 5 – 7 we present the photometry for the sample from the Spitzer , Herschel , and WISE space observatories, respectively. Spitzer photometric data only exist for the original sample of 15 sources, while Herschel and WISE data are shown for the full sample of 33. Table 5 Spitzer Photometric Data Note. Column (1): galaxy ID. Columns (2)–(5): Spitzer IRAC flux densities. Column (6): IRAC 8 μ m FWHM. Computed as the geometric mean of the major and minor axes of 2D elliptical Gaussian. Column (7): ratio of synthetic IRAC 8 μ m, computed from the IRS spectrum, to global 8 μ m; used for spectral scaling of SL. Columns (8)–(10): Spitzer MIPS flux densities. Column (11):
Paper: 2019MNRAS.486.4130L (acknowledgments)
ACKNOWLEDGEMENTS We thank Chris Thompson and the anonymous referee for comments that helped to clarify the presentation of this work. SKL acknowledges support from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 665778, via fellowship UMO-2016/21/P/ST9/03689 of the National Science Centre, Poland. Both authors thank the PHAROS COST Action (CA16214) for partial support. This work used the DiRAC@Durham facility managed by the Institute for Computational Cosmology on behalf of the STFC DiRAC HPC Facility ( www.dirac.ac.uk ). The equipment was funded by BEIS capital funding via STFC capital grants ST/P002293/1, ST/R002371/1, and ST/S002502/1, Durham University and STFC operations grant ST/R000832/1. DiRAC is part of the National e-Infrastructure.