adsabs/WIESP2022-NER huggingface dataset:
Paper: 2018ApJ...867...27N (fulltext)
that minihalos that have been chemically enriched by supernova ejecta from prior Population III star formation can cool and form stars and, moreover, significantly contribute to the overall ionizing photon budget of reionization. We refer to this new class of halos as metal-line cooling halos, or MCs. Follow-on simulations (the Renaissance Simulations) in much larger volumes by Xu et al. ( 2016b ) provide the star formation rates (SFRs), intermittency, and ionizing escape fractions in the MCs, LMACHs, and HMACHs with extremely high resolution and good statistics. Using these results as our input, we revisit the problem: what is the role of the lowest-mass halos in the reionization process? The main improvement of our work compared with previous work is that the simulations shown here are fully coupled cosmological radiation hydrodynamic simulations, with a time-dependent treatment of the ionization kinetics and emissivities assigned to the source halos dynamically, considering the intermittency of the contribution from MCs. We find that because star formation is intermittent in MCs, the earliest phases of reionization exhibit a stochastic nature, with small H ii regions forming and recombining. Only later, after the characteristic halo mass scale has reached ∼10 9 , does reionization proceed smoothly in the usual manner deduced from earlier studies. Adopting concordance cosmological parameters and only using the galaxy properties from the Renaissance Simulations, our 1152 3 simulation in a 14.4 comoving Mpc box begins reionizing at z = 20, is 10% ionized at z = 10, and fully ionizes at z = 7.1. This paper is organized as follows. We summarize the relevant results from Xu et al. ( 2016b ) in Section 2 . The description of computational method and inputs to the simulations is provided in Section 3 . We show results in Section 4 and offer a discussion and conclusions in Section 5 . 2. Ionizing Photons from the Smallest Galaxies Unlike the previous papers in this series (So et al. 2014 ; Norman et al. 2015 ), where ionizing emissivities were calculated from a simple star formation/feedback recipe incorporated in the simulation itself, here we employ results from much higher resolution simulations that calculate the escaping ionizing photons of high-redshift galaxies directly. How this is done is described in Sections 3.2 and 3.3 . This approach enormously relaxes the spatial resolution requirement on the global reionization simulation and takes advantage of more precise simulation results. Uniform grids may be employed for the reionization simulation; however, they must have sufficient mass and spatial resolution to accurately capture the halo population of importance. In addition, we are able to use moment methods for the radiation transport, which do not get bogged down as reionization completes as some ray-tracing methods do (Norman et al. 2015 ). We draw on the results of Xu et al. ( 2016b ), who performed three high-resolution AMR
Paper: 2016A&A...585A..41W (fulltext)
of for the central beam ( top ) and an offset beam ( bottom ) with a coma lobe at a position angle of . For the correction algorithm, we averaged the previously modeled side-lobe intensities on a fixed grid containing 2160 cells in cylindrical coordinates for the inner of the antenna diagrams. The cells have an azimuthal extent of and a radial extent of , covering the radial range of (first minimum) up to . 3.5.4. The far side lobes The far side lobes are determined by details of the telescope structure. It is difficult to measure these side lobes (e.g., Higgs 1967 ; Hartsuijker et al. 1972 ), so we used ray-tracing to model them. While in the near side-lobe range, details of each of the individual antenna diagrams need to be considered, and it is sufficient to use a single common far side-lobe diagram for all of the receivers. For the subsequent discussion of far-side-lobe effects, we consider the telescope as a transmitting system. The most important side lobes that are far away from the main beam of the 100-m telescope, were determined by Kalberla et al. (1980a, see their Fig. 3) . These are the stray cones, caused by reflection of plane waves from the primary mirror at the feed support legs. The second most important structure is the spill-over at the edge of the main reflector. Its irradiation level depends on the edge taper of the primary feeds. In addition, we considered spherical waves originating in the feeds and determined their reflections at the support legs. Figure 6 shows these structures. The eightfold symmetry is caused by the four legs. Each leg consists of four main tubes; two of them, separated by 1.98 m, are visible from the feed. These side lobes have an interesting structure, but it turned out that they are rather unimportant. Fig. 6 Side lobes caused by reflections of spherical waves from the feed at the support legs of the 100-m (intensities relative to main beam). The Effelsberg 100-m telescope has a Gregorian secondary focus with several feed systems in an apex cabin. The seven-feed system is situated in primary focus, and the roof of the apex cabin is closed during EBHIS observations. This roof causes reflections that are offset from the main axis by . The side lobes are easily determined from the geometry of the apex roof. However, that these reflections are oriented in the east-west direction makes the situation very uncomfortable since it can produce multiple reflections. A part of the rays being reflected off the apex roof can hit feed support legs located east or west of the roof. This causes secondary stray cones. Only a fraction of these secondary stray cones are reflected onto the sky. The other part is reflected to the main mirror, causing caustics. A minor fraction of the secondary stray cones can hit the fence at the rim of the reflector before escaping. These features were determined by ray-tracing. Figure 7 shows the resulting pattern. We disregarded further reflections caused by support legs to the
Paper: 2021MNRAS.500.1992T (fulltext)
dipolar signal exists for HD 41641, as the model fits extremely poorly, fitting extremely few of the features visible in the LSD profiles. To ensure that the fitting process had converged properly, it was repeated several times with various first guess parameters, while also rejecting the region of the main spot within the profile when fitting the Stokes I spectra prior to modelling. The results of the modelling are listed as follows. We determined two combinations of inclination and obliquity angles, which effectively corresponds to i = 70° ± 5° and β = 30° ± 5°, and i = 30° ± 5° and β = 70° ± 5°, both with χ 2 = 1.875. The model also suggests a phase shift Δψ = 0.0738 ± 0.005 and, assuming it is a dipole, a maximum polar field strength of B pol = 1880 ± 10 G. The best-fitting model is visible in Fig. 6 . We stress that the dipolar fit to the data is very poor and the above values must therefore be considered with great care and are provided here only to give an idea of the amplitude of the magnetic field signature. This model again shows that a dipolar fit is not appropriate for this star. Figure 6. Results of dipolar modelling performed on the 16 best profiles. Profiles are ordered in phase, increasing vertically first then horizontally. Model fit is displayed as red overlay. Comparing the results determined here for i , β, and B pol with those calculated in Section 3.2 , it is clear there is quite an offset, though this is expected as a result of the poor-fitting dipolar modelling. We do however see a match between the calculated values of β = 79° ± 11° and i = 22° ± 11° and the model with values of β = 70° ± 5° and i = 30° ± 5°. Finally, the error bar of the calculated B pol looks far more reasonable than the range of possible values determined by the dipolar modelling in Section 3.2 , but considering the bad fit we obtain, this error bar is not realistic. 4 CONCLUSIONS We carried out a spectropolarimetric study of the δ Sct star HD 41641, complementing the findings of E16 . We utilized data taken with the NARVAL echelle spectropolarimeter from 2015 October 21 to 2016 December 2. The spectra were used to determine the existence and possible origin of the magnetic field of HD 41641, as well as confirm some of the stellar parameters as determined by E16 . First of all, we confirm that HD 41641 is indeed magnetic, making it the fourth magnetic δ Sct star discovered to date. Through our subsequent analysis, we determined that a different rotation frequency than the one suggested by E16 fit the data more accurately. Switching from a frequency of 0.17756 to 0.3560 d −1 revealed a periodic variation in the magnetic field measurements and in the LSD Stokes I profiles. As a result, some of the other stellar parameters calculated by E16 , such as the inclination i , were no longer suitable and required recalculation. The new value for i was determined to be i = 22° ± 11° and the magnetic obliquity angle β, assuming a dipolar field, was found to be
Paper: 2020MNRAS.491.4247H (acknowledgments)
ACKNOWLEDGEMENTS MRL is supported by a COFUND/Durham Junior Research Fellowship under EU grant 609412 and also by a Grant of Excellence from the Icelandic Research Fund (grant number 173929051). This work was carried out on the Dutch National e-Infrastructure with the support of SURF Cooperative. We would also like to thank Dr. Benjamin Oppenheimer for contributing his simulations of cold dark matter, without which we would not have been able to complete this project. DH is supported by the D-ITP consortium, a program of the Netherlands Organization for Scientific Research (NWO) that is funded by the Dutch Ministry of Education, Culture and Science (OCW). This work is supported by the Swiss National Science Foundation (SNSF). This project has received funding form the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (COSMICLENS: grant agreement No. 787886
Paper: 2016MNRAS.457.1198C (fulltext)
In the second approach, as a consistency check, we performed an unconstrained fit by allowing for the bulge age to vary between 16.4 and 18.0 Gyr (on steps of 0.2 Gyr) and bulge iron abundance to vary between 0.10 and 0.16 dex (on steps of 0.02 dex) to account for the adopted uncertainties on the bulge properties. For the NSD, we explored the same ranges of age and iron abundance as for the constrained fit. The resulting best-fitting model requires a bulge with t bulge = 18.0 Gyr and [Fe/H] bulge = 0.16 dex and an NSD with t NSD = 3.2 Gyr and [Fe/H] NSD = 0.50 dex (Fig. 5 ). In both cases, we conclude that the NSD of NGC 1023 is much younger and more metal rich than the host bulge. The age of the NSD is well constrained, whereas the its iron abundance corresponds to the upper limit of the [Fe/H] range of the available SSP models. Without the knowledge of the light fraction of NSD, the age and metallicity of the NSD can be hardly recovered due to the degeneracy between these two parameters (see Sarzi et al. 2016 , for a discussion). 4 DISCUSSION AND CONCLUSIONS The structure and properties of the stellar population of the nuclear region of the interacting SB0 galaxy NGC 1023 were investigated through a detailed analysis of archival HST imaging and ground-based integral-field spectroscopy. The galaxy is known to host a highly inclined NSD (Faber et al. 1997 ; Sil'chenko 1999 ; Sarzi et al. 2006 ; Ledo et al. 2010 ). Moreover, the stars of the galaxy nucleus have significantly different chemical properties with respect to the surrounding bulge. They are younger, more metal rich, and have a higher magnesium overabundance (Sil'chenko 1999 ; McDermid et al. 2006 ; Kuntschner et al. 2010 ). In this paper, we derived the central surface brightness, scalelength, inclination, and position angle of the NSD of NGC 1023 in all the available broad-band HST images by assuming that it is an infinitesimally thin exponential disc. We applied the photometric decomposition method of Scorza Bender ( 1995 ) and adopted the algorithm by Morelli et al. ( 2004 , 2010 ), which we implemented for a better determination of the best-fitting parameters. The location and orientation of the NSD do not depend on the observed passband, as already observed for the few other NSDs for which a detailed multiband photometric analysis was performed (Krajnović Jaffe 2004 ; Morelli et al. 2010 ; Corsini et al. 2012 ) whereas the NSD appears more concentrated in the bluer image. We measured the light contribution of the NSD to the total luminosity of the galaxy L NSD / L T in the same concentric circular rings centred on the galaxy nucleus where the equivalent widths of the Lick/IDS line-strength indices were obtained from ground-based integral-field spectroscopy by Sil'chenko ( 1999 ). In the WFPC2/ F555W passband the NSD contributes a maximum of 6 per cent of the total luminosity within the innermost circular aperture ( R 0.65 arcsec), whereas all the galaxy light is given by the
Paper: 2018A&A...612L...2K (fulltext)
to give a more reliable answer on the issue of zero point of the v sin i data. On the other hand, by checking other (even though sparse and, in general, less accurate) data sources on Praesepe ( Cummings et al. 2017 ; Quinn et al. 2012 ; Pace Pasquini 2004 ; Boesgaard et al. 2004 ; Rachford 1998 ; Malavolta et al. 2016 ; Mann et al. 2017 ) we find that most of the published values (~ 80%) are an average of 10–20% higher than our values. Therefore, we think that the current data lend support to a non-isotropic inclination angle distribution rather than to the isotropic one. Fig. 4 Observed cumulative distributions of sin i and the associated model distributions assuming isotropic and cone distributions (see Jackson et al. 2010 ) for the inclination angle. See Table 3 for the ( α , λ ) parameters used in the cone distributions. The error bars correspond to 1 σ limits derived from the random simulations of the theoretical CDFs. To avoid crowding, we show them only for the isotropic distributions because the errors for the cone distributions are very similar. For the other datasets we see a comfortable overall consistency between the expected distributions and the best fitting models. The optimal cone models (with large parameter scatter, as expected) are indistinguishable from the isotropic model for all field star samples, although there is a slight indication for the underestimation of the observational noise for Field (C): the observed CDF is shallower than that of the isotropic distribution. The opposite is likely to be true for the planetary host samples, especially for the KOI sample. We find that decreasing the noise on v sin i by a factor of two (relative to the values given by Winn et al. 2017 ), the fit improves substantially with σ cone = 0.028 ± 0.008 and cone parameters α = 80 ° ± 11 ° and λ = 27 ° ± 18 ° . These cone parameters may imply the presence of some oblique systems in the KOI sample. Instead of making any far-reaching conclusion of this sort from this test alone, we refer to Hirano et al. (2014) and Winn et al. (2017) for further discussion of the topic. However, we draw attention to the importance of proper noise estimation when modeling the distribution of the inclination angles from spectroscopic rotation velocities. 5 Conclusions By using recently determined stellar rotation periods, available spectroscopic rotation velocities, and evolutionary stellar radii based on IRFM-calibrated effective temperatures, we derived the distribution of the line-of-sight inclination angles from 113 main sequence F − K stars in the Praesepe open cluster. With the aid of statistical modeling, we found signatures of a broad rotational axis alignment. The cone model of Jackson et al. (2010) yielded an overall cone axis angle of 76 ° ± 14 ° and an opening angle of 47 ° ± 24 ° . Isotropic angle distribution is far less likely, except when the spectroscopic rotational velocities used in this work are systematically overestimated. Although we
Paper: 2019ApJ...885...69L (acknowledgments)
We thank Kaitlin Kratter, Paola Pinilla, Philip Pinto, and Peter Behroozi for useful discussions. R.L. acknowledges support from NASA headquarters under the NASA Earth and Space Science Fellowship Program grant NNX16AP53H. A.N.Y. acknowledges partial support from NASA Astrophysics Theory Grant NNX17AK59G and from the NSF through grant AST-1616929. Software: ATHENA (Stone et al. 2008 ; Bai Stone 2010c ), Matplotlib (Hunter 2007 ), Numpy Scipy (Jones et al. 2001 ), emcee v3.0rc2 (Foreman-Mackey et al. 2013 ), PLAN (Li 2019a ), Pyridoxine (Li 2019b ).
Paper: 2021A&A...649A.171A (fulltext)
a few megahertz, and this is the reason why some of the unidentified lines seen in the 80–116 GHz range were not properly assigned to CHD 2 CCH and CH 2 DCCD by Agúndez et al. (2019) . In fact, the identification of these two molecules drastically reduces the number of lines pending identification in the λ 3 mm line survey of L483 (see Table A.2 of Agúndez et al. 2019 ). The parameters derived for the lines assigned to the two doubly deuterated isotopologues of methyl acetylene are given in Table 1 and the observed line profiles are shown in Fig. 1 for CHD 2 CCH and in Fig. 2 for CH 2 DCCD. We note that the line at 91971.307 MHz, assigned to the 6 1,6 –5 1,5 transition ofCHD 2 CCH, was incorrectly assigned to the transition 5 3 –4 3 F = 6–5 of CH 3 CN by Agúndez et al. (2019) . The astronomical frequencies observed in the 72–116 GHz range (see Table 1 ) and the laboratory frequencies measured inthe 29–47 GHz range ( Thomas et al. 1955 ) were used to derive more accurate spectroscopic parameters for CHD 2 CCH and CH 2 DCCD (see Table 2 ). These constants are a considerable improvement on those reported by Thomas et al. (1955) and enable us to predict the rotational spectrum of the two molecules with an accuracy better than 0.1 MHz up to 200 GHz. Since the lines of doubly deuterated CH 3 CCH are relatively bright in L483, it would not be surprising to detect the triply deuterated species CHD 2 CCD, which should be three times more abundant than CD 3 CCH. However, the rotational spectrum has only been measured in the 28–43 GHz range with modest accuracy ( Thomas et al. 1955 ), which may translate to frequency errors of a few megahertz for lines lying above 72 GHz. It would therefore be interesting to measure the rotational spectrum of triply deuterated CH 3 CCH at millimeter wavelengths. Table 1 Observed line parameters of CHD 2 CCH and CH 2 DCCD in L483. Notes. Numbers in parentheses are 1 σ uncertainties in units of the last digits. Line parameters were derived from a Gaussian fit to the line profile. Observed frequencies are obtained adopting V LSR = 5.30 km s −1 ( Agúndez et al. 2019 ) and have an uncertainty of 20 kHz for all the lines. The full width at half maximum is Δ v . 3.2 Observed column densities We derived beam-averaged column densities for methyl acetylene and its singly and doubly deuterated isotopologues in L483 assuming local thermodynamic equilibrium. Values for CH 3 CCH and the two singly deuterated forms were already reported by Agúndez et al. (2019) . Here we have revised some of these values including new lines observed in the 72–80 GHz range and using new values for the electric dipole moments. The dipole moment of CH 3 CCH was experimentally measured by Burrell et al. (1980) to be 0.7839 D. For CH 3 CCD, the dipole moment was measured by Muenter Laurie (1966) . Here, we adopt the value measured by these latter authors corrected by using a more accurate value of the dipole moment of OCS, which is used as reference (see
Paper: 2015ApJ...814...74J (acknowledgments)
We are grateful to an anonymous referee for constructive comments, and Hailiang Chen and Thomas Tauris for helpful discussions. This work was supported by the Natural Science Foundation of China under grant nos. 11133001 and 11333004, the Strategic Priority Research Program of CAS under grant no. XDB09010200, and the Munich Institute for Astro- and Particle Physics (MIAPP) of the DFG cluster of excellence “Origin and Structure of the universe.”
Paper: 2017MNRAS.471..210G (acknowledgments)
Acknowledgements DG, MB and IP acknowledge support from PRIN-INAF 2014 (PI M. Bondi). DG and IP acknowledge support of the Ministry of Foreign Affairs and International Cooperation, Directorate General for the Country Promotion (Bilateral Grant Agreement ZA14GR02 – Mapping the Universe on the Pathway to SKA).
Paper: 2017MNRAS.470.4698A (acknowledgments)
Acknowledgments We thank C.R. Christensen, R. Davé, S. Genel, Z. Hafen, A.V. Kravtsov, M. Kriek, A.L. Muratov, B. D. Oppenheimer, A. J. Richings, J. Rojas-Sandoval, R. S. Somerville and S. Veilleux for useful discussions. We greatly appreciate the referee’s thoughtful comments that helped us improve the paper in several places. DAA acknowledges support by a CIERA Postdoctoral Fellowship. CAFG was supported by NSF through grants AST-1412836 and AST-1517491, by NASA through grant NNX15AB22G and by STScI through grants HST-AR-14293.001-A and HST-GO-14268.022-A. DK was supported by NSF grant AST-1412153 and a Cottrell Scholar Award. Support for PFH was provided by an Alfred P. Sloan Research Fellowship, NASA ATP Grant NNX14AH35G, and NSF Collaborative Research Grant #1411920 and CAREER grant #1455342. EQ was supported by NASA ATP grant 12-ATP12-0183, a Simons Investigator award from the Simons Foundation, and the David and Lucile Packard Foundation. The simulations analysed in this paper were run using the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by NSF grant ACI-1053575 (allocations TG-AST120025, TG-AST130039 and TG-AST140023). This work greatly benefited from the hospitality of the Aspen Center for Physics, supported by NSF grant PHY-1066293.
Paper: 2019MNRAS.485.3009H (acknowledgments)
ACKNOWLEDGEMENTS PH acknowledges receipt of a Science and Technologies Facilities Council (STFC) studentship. HVA acknowledges the Spanish Plan Nacional de Astronomía y Astrofisća under grant AYA2016-76682-C3-2-P. The European VLBI Network is a joint facility of independent European, African, Asian, and North American radio astronomy institutes. Scientific results from data presented in this publication are derived from the following EVN project codes: EJ016A and EJ016B. e-MERLIN is a National Facility operated by the University of Manchester at Jodrell Bank Observatory on behalf of STFC. We also thank James Nightingale for a helpful discussion on model optimization and the anonymous referee for helpful comments.