Recursos de colección

Caltech Authors (171.365 recursos)

Repository of works by Caltech published authors.

Group = NuSTAR

Mostrando recursos 1 - 20 de 575

  1. Discovery of Pulsation Dropout and Turn-on during the High State of the Accreting X-Ray Pulsar LMC X-4

    Brumback, McKinley C.; Hickox, Ryan C.; Bachetti, Matteo; Ballhausen, Ralf; Fürst, Felix S.; Pike, Sean; Pottschmidt, Katja; Tomsick, John A.; Wilms, Jörn
    Two Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the luminous X-ray pulsar LMC X-4 in 2015 October and November captured several bright accretion flares from this source, which has a long history of stable pulse and superorbital behavior. We present a timing analysis of these data in which we detect a rapid pulse "turn-on" in association with the accretion flares, during which the source reaches super-Eddington luminosities. Pulsations, which are normally seen from this source, are found to only occur for approximately one hour before and during the bright flares. Beyond one hour before and after the flares, we find...

  2. An Iwasawa-Taniguchi Effect for Compton-thick Active Galactic Nuclei

    Boorman, Peter G.; Gandhi, Poshak; Baloković, Mislav; Brightman, Murray; Harrison, Fiona; Ricci, Claudio; Stern, Daniel
    We present the first study of an Iwasawa–Taniguchi/‘X-ray Baldwin’ effect for Compton-thick active galactic nuclei (AGN). We report a statistically significant anticorrelation between the rest-frame equivalent width (EW) of the narrow core of the neutral Fe Kα fluorescence emission line, ubiquitously observed in the reflection spectra of obscured AGN, and the mid-infrared 12μm continuum luminosity (taken as a proxy for the bolometric AGN luminosity). Our sample consists of 72 Compton-thick AGN selected from pointed and deep-field observations covering a redshift range of z ∼ 0.0014−3.7. We employ a Monte Carlo-based fitting method, which returns a Spearman’s Rank correlation coefficient of ρ =...

  3. The 1.5 Ms observing campaign on IRAS 13224−3809 – I. X-ray spectral analysis

    Jiang, J.; Parker, M. L.; Fabian, A. C.; Alston, W. N.; Buisson, D. J. K.; Cackett, E. M.; Chiang, C.-Y.; Dauser, T.; Gallo, L. C.; García, J. A.; Harrison, F. A.; Lohfink, A. M.; De Marco, B.; Kara, E.; Miller, J. M.; Miniutti, G.; Pinto, C.; Walton, D. J.; Wilkins, D. R.
    We present a detailed spectral analysis of the recent 1.5 Ms XMM–Newton observing campaign on the narrow-line Seyfert 1 galaxy IRAS 13224−3809, taken simultaneously with 500 ks of NuSTAR data. The X-ray light curve shows three flux peaks, registering at about 100 times the minimum flux seen during the campaign, and rapid variability with a time-scale of kiloseconds. The spectra are well fit with a primary power-law continuum, two relativistic-blurred reflection components from the inner accretion disc with very high iron abundance, and a simple blackbody-shaped model for the remaining soft excess. The spectral variability is dominated by the power-law continuum from...

  4. Young Accreting Compact Objects in M31: The Combined Power of NuSTAR, Chandra, and Hubble

    Lazzarini, M.; Hornschemeier, A. E.; Williams, B. F.; Wik, D.; Vulic, N.; Yukita, M.; Zezas, A.; Lewis, A. R.; Durbin, M.; Ptak, A.; Bodaghee, A.; Lehmer, B. D.; Antoniou, V.; Maccarone, T.
    We present 15 high mass X-ray binary (HMXB) candidates in the disk of M31 for which we are able to infer compact object type, spectral type of the donor star, and age using multiwavelength observations from NuSTAR, Chandra, and the Hubble Space Telescope (HST). The hard X-ray colors and luminosities from NuSTAR permit the tentative classification of accreting X-ray binary systems by compact object type, distinguishing black hole from neutron star systems. We find hard state black holes, pulsars, and non-magnetized neutron stars associated with optical point source counterparts with similar frequency. We also find nine non-magnetized neutron stars coincident with globular clusters and an equal number of pulsars...

  5. A tale of two periods: determination of the orbital ephemeris of the super-Eddington pulsar NGC 7793 P13

    Fürst, F.; Walton, D. J.; Heida, M.; Harrison, F. A.; Barret, D.; Brightman, M.; Fabian, A. C.; Middleton, M. J.; Pinto, C.; Rana, V.; Tramper, F.; Webb, N.; Kretschmar, P.
    We present a timing analysis of multiple XMM-Newton and NuSTAR observations of the ultra-luminous pulsar NGC 7793 P13 spread over its 65d variability period. We use the measured pulse periods to determine the orbital ephemeris, confirm a long orbital period with P_orb = 63.9 (+0.5,-0.6) d, and find an eccentricity of e <= 0.15. The orbital signature is imprinted on top of a secular spin-up, which seems to get faster as the source becomes brighter. We also analyse data from dense monitoring of the source with Swift and find an optical photometric period of 63.9 +/- 0.5 d and an X-ray flux period of 66.8 +/- 0.4 d....

  6. Radio/X-ray monitoring of the broad-line radio galaxy 3C 382. High-energy view with XMM–Newton and NuSTAR

    Ursini, F.; Petrucci, P.-O.; Matt, G.; Bianchi, S.; Cappi, M.; Dadina, M.; Grandi, P.; Torresi, E.; Ballantyne, D. R.; De Marco, B.; De Rosa, A.; Giroletti, M.; Malzac, J.; Marinucci, A.; Middei, R.; Ponti, G.; Tortosa, A.
    We present the analysis of five joint XMM–Newton/NuSTARobservations, 20 ks each and separated by 12 days, of the broad-line radio galaxy 3C 382. The data were obtained as part of a campaign performed in September-October 2016 simultaneously with VLBA. The radio data and their relation with the X-ray ones will be discussed in a following paper. The source exhibits a moderate flux variability in the UV/X-ray bands, and a limited spectral variability especially in the soft X-ray band. In agreement with past observations, we find the presence of a warm absorber, an iron Kα line with no associated Compton reflection...

  7. Recurring obscuration in NGC 3783

    Kaastra, J. S.; Mehdipour, M.; Behar, E.; Bianchi, S.; Branduardi-Raymont, G.; Brenneman, L.; Cappi, M.; Costantini, E.; De Marco, B.; di Gesu, L.; Ebrero, J.; Kriss, G. A.; Mao, J.; Peretz, U.; Petrucci, P.-O.; Ponti, G.; Walton, D. J.
    Obscuration of the continuum emission from active galactic nuclei by streams of gas with relatively high velocity (> 1000 km/s) and column density (>3E25 per m^2) has been seen in a few Seyfert galaxies. This obscuration has a transient nature. In December 2016 we have witnessed such an event in NGC 3783. The frequency and duration of these obscuration events is poorly known. Here we study archival data of NGC 3783 in order to constrain this duty cycle. We use archival Chandra/NuSTAR spectra taken in August 2016. We also study the hardness ratio of all Swift XRT spectra taken between 2008-2017. In August 2016, NGC 3783 also showed...

  8. A curious case of the accretion-powered X-ray pulsar GX 1+4

    Jaisawal, Gaurava K.; Naik, Sachindra; Gupta, Shivangi; Chenevez, Jérôme; Epili, Prahlad
    We present detailed spectral and timing studies using a NuSTAR observation of GX 1+4 in 2015 October during an intermediate-intensity state. The measured spin period of 176.778 s is found to be one of the highest values since its discovery. In contrast to a broad sinusoidal-like pulse profile, a peculiar sharp peak is observed in profiles below ∼25 keV. The profiles at higher energies are found to be significantly phase shifted compared to the soft X-ray profiles. Broad-band energy spectra of GX 1+4, obtained from NuSTAR and Swiftobservations, are described with various continuum models. Among these, a two-component model consisting...

  9. A Potential Cyclotron Resonant Scattering Feature in the Ultraluminous X-Ray Source Pulsar NGC 300 ULX1 Seen by NuSTAR and XMM-Newton

    Walton, D. J.; Bachetti, M.; Fürst, F.; Barret, D.; Brightman, M.; Fabian, A. C.; Grefenstette, B. W.; Harrison, F. A.; Heida, M.; Kennea, J.; Kosec, P.; Lau, R. M.; Madsen, K. K.; Middleton, M. J.; Pinto, C.; Steiner, J. F.; Webb, N.
    Based on phase-resolved broadband spectroscopy using XMM-Newton and NuSTAR, we report on a potential cyclotron resonant scattering feature (CRSF) at E ~ 13 keV in the pulsed spectrum of the recently discovered ultraluminous X-ray source (ULX) pulsar NGC 300 ULX1. If this interpretation is correct, the implied magnetic field of the central neutron star is B ~ 1012 G (assuming scattering by electrons), similar to that estimated from the observed spin-up of the star, and also similar to known Galactic X-ray pulsars. We discuss the implications of this result for the connection between NGC 300 ULX1 and the other known...

  10. Broadband X-ray Spectral Analysis of the Double-Nucleus Luminous Infrared Galaxy Mrk 463

    Yamada, Satoshi; Ueda, Yoshihiro; Oda, Saeko; Tanimoto, Atsushi; Imanishi, Masatoshi; Terashima, Yuichi; Ricci, Claudio
    We present a broadband (0.4–70 keV) X-ray spectral analysis of the luminous infrared galaxy (LIRG) system Mrk 463 observed with Nuclear Spectroscopic Telescope Array (NuSTAR), Chandra, and XMM-Newton, which contains double active galactic nuclei (AGNs; Mrk 463E and Mrk 463W) with a separation of ~3.8 kpc. Detecting their transmitted hard X-ray >10 keV continua with NuSTAR, we confirm that Mrk 463E and Mrk 463W have AGNs with intrinsic luminosities of (1.6–2.2) × 10^(43) and (0.5–0.6) × 10^(43) erg s^(−1) (2–10 keV) obscured by hydrogen column densities of 8 × 10^(23) and 3 × 10^(23) cm^(−2), respectively. Both nuclei show strong...

  11. NuSTAR Detection of X-Ray Heating Events in the Quiet Sun

    Kuhar, Matej; Krucker, Säm; Glesener, Lindsay; Hannah, Iain G.; Grefenstette, Brian W.; Smith, David M.; Hudson, Hugh S.; White, Stephen M.
    The explanation of the coronal heating problem potentially lies in the existence of nanoflares, numerous small-scale heating events occurring across the whole solar disk. In this Letter, we present the first imaging spectroscopy X-ray observations of three quiet Sun flares during the Nuclear Spectroscopic Telescope ARray (NuSTAR) solar campaigns on 2016 July 26 and 2017 March 21, concurrent with the Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) observations. Two of the three events showed time lags of a few minutes between peak X-ray and extreme ultraviolet emissions. Isothermal fits with rather low temperatures in the range 3.2–4.1 MK and emission measures...

  12. A Potential Cyclotron Resonant Scattering Feature in the Ultraluminous X-Ray Source Pulsar NGC 300 ULX1 Seen by NuSTAR and XMM-Newton

    Walton, D. J.; Bachetti, M.; Fürst, F.; Barret, D.; Brightman, M.; Fabian, A. C.; Grefenstette, B. W.; Harrison, F. A.; Heida, M.; Kennea, J.; Kosec, P.; Lau, R. M.; Madsen, K. K.; Middleton, M. J.; Pinto, C.; Steiner, J. F.; Webb, N.
    Based on phase-resolved broadband spectroscopy using XMM-Newton and NuSTAR, we report on a potential cyclotron resonant scattering feature (CRSF) at E ~ 13 keV in the pulsed spectrum of the recently discovered ultraluminous X-ray source (ULX) pulsar NGC 300 ULX1. If this interpretation is correct, the implied magnetic field of the central neutron star is B ~ 1012 G (assuming scattering by electrons), similar to that estimated from the observed spin-up of the star, and also similar to known Galactic X-ray pulsars. We discuss the implications of this result for the connection between NGC 300 ULX1 and the other known...

  13. Multi-wavelength campaign on NGC 7469 IV. The broad-band X-ray spectrum

    Middei, R.; Bianchi, S.; Cappi, M.; Petrucci, P.-O.; Ursini, F.; Arav, N.; Behar, E.; Branduardi-Raymont, G.; Costantini, E.; De Marco, B.; Di Gesu, L.; Ebrero, J.; Kaastra, J.; Kaspi, S.; Kriss, G. A.; Mao, J.; Mehdipour, M.; Paltani, S.; Peretz, U.; Ponti, G.
    We conducted a multi-wavelength six-month campaign to observe the Seyfert galaxy NGC 7469, using the space-based observatories HST, Swift, XMM-Newton and NuSTAR. Here we report the results of the spectral analysis of the 7 simultaneous XMM-Newton and NuSTAR observations. The sources shows significant flux variability within each observation, but the average flux is less variable among the different pointings of our campaign. Our spectral analysis reveals a prominent narrow neutral Fe kα emission line in all the spectra, with weaker contributions from Fe Kβ, neutral Ni Kα and ionised iron. We find no evidence for variability or relativistic effects acting on the emission lines, which...

  14. Evidence for Pulsar-like Emission Components in the Broadband ULX Sample

    Walton, D. J.; Fürst, F.; Heida, M.; Harrison, F. A.; Barret, D.; Stern, D.; Bachetti, M.; Brightman, M.; Fabian, A. C.; Middleton, M. J.
    We present broadband X-ray analyses of a sample of bright ultraluminous X-ray sources (ULX) with the goal of investigating the spectral similarity of this population to the known ULX pulsars, M82 X-2, NGC 7793 P13, and NGC 5907 ULX. We perform a phase-resolved analysis of the broadband XMM-Newton+NuSTAR data set of NGC 5907 ULX, finding that the pulsed emission from the accretion column in this source exhibits a similar spectral shape to that seen in both M82 X-2 and NGC 7793 P13, and that this is responsible for the excess emission observed at the highest energies when the spectra are...

  15. The NuSTAR Extragalactic Surveys: Source Catalog and the Compton-thick Fraction in the UDS Field

    Masini, A.; Civano, F.; Comastri, A.; Fornasini, F.; Ballantyne, D. R.; Lansbury, G. B.; Treister, E.; Alexander, D. M.; Boorman, P. G.; Brandt, W. N.; Farrah, D.; Gandhi, P.; Harrison, F. A.; Hickox, R. C.; Kocevski, D. D.; Lanz, L.; Marchesi, S.; Puccetti, S.; Ricci, C.; Saez, C.; Stern, D.; Zappacosta, L.
    We present the results and the source catalog of the NuSTAR survey in the UKIDSS Ultra Deep Survey (UDS) field, bridging the gap in depth and area between NuSTAR's ECDFS and COSMOS surveys. The survey covers a ~0.6 deg^2 area of the field for a total observing time of ~1.75 Ms, to a half-area depth of ~155 ks corrected for vignetting at 3–24 keV, and reaching sensitivity limits at half-area in the full (3–24 keV), soft (3–8 keV), and hard (8–24 keV) bands of 2.2 × 10^(−14) erg cm^(−2) s^(−1), 1.0 × 10^(−14) erg cm^(−2) s^(−1), and 2.7 × 10^(−14)...

  16. Discovery of pulsations from NGC 300 ULX1 and its fast period evolution

    Carpano, S.; Haberl, F.; Maitra, C.; Vasilopoulos, G.
    The supernova impostor SN 2010da located in the nearby galaxy NGC 300, later identified as a likely supergiant B[e] high-mass X-ray binary, was simultaneously observed by NuSTAR and XMM–Newton between 2016 December 16 and 20, over a total time span of ∼310 ks. We report the discovery of a strong periodic modulation in the X-ray flux with a pulse period of 31.6 s and a very rapid spin-up, and confirm therefore that the compact object is a neutron star. We find that the spin period is changing from 31.71 s to 31.54 s over that period, with a spin-up rate of −5.56 × 10^(−7) s s^(−1),...

  17. The NuSTAR Extragalactic Surveys: Source Catalog and the Compton-thick Fraction in the UDS Field

    Masini, A.; Civano, F.; Comastri, A.; Fornasini, F.; Ballantyne, D. R.; Lansbury, G. B.; Treister, E.; Alexander, D. M.; Boorman, P. G.; Brandt, W. N.; Farrah, D.; Gandhi, P.; Harrison, F. A.; Hickox, R. C.; Kocevski, D. D.; Lanz, L.; Marchesi, S.; Puccetti, S.; Ricci, C.; Saez, C.; Stern, D.; Zappacosta, L.
    We present the results and the source catalog of the NuSTAR survey in the UKIDSS Ultra Deep Survey (UDS) field, bridging the gap in depth and area between NuSTAR's ECDFS and COSMOS surveys. The survey covers a ~0.6 deg2 area of the field for a total observing time of ~1.75 Ms, to a half-area depth of ~155 ks corrected for vignetting at 3–24 keV, and reaching sensitivity limits at half-area in the full (3–24 keV), soft (3–8 keV), and hard (8–24 keV) bands of 2.2 × 10−14 erg cm−2 s−1, 1.0 × 10−14 erg cm−2 s−1, and 2.7 × 10−14...

  18. The Evolution of GX 339-4 in the Low-hard State as Seen by NuSTAR and Swift

    Wang-Ji, Jingyi; García, Javier A.; Steiner, James F.; Tomsick, John A.; Harrison, Fiona A.; Bambi, Cosimo; Petrucci, Pierre-Olivier; Ferreira, Jonathan; Chakravorty, Susmita; Clavel, Maïca
    We analyze 11 Nuclear Spectroscopic Telescope Array and Swift observations of the black hole X-ray binary GX 339–4 in the hard state, 6 of which were taken during the end of the 2015 outburst and 5 during a failed outburst in 2013. These observations cover luminosities from 0.5% to 5% of the Eddington luminosity. Implementing the most recent version of the reflection model relxillCp, we perform simultaneous spectral fits on both data sets to track the evolution of the properties in the accretion disk, including the inner edge radius, the ionization, and the temperature of the thermal emission. We also...

  19. Evidence for a Variable Ultrafast Outflow in the Newly Discovered Ultraluminous Pulsar NGC 300 ULX-1

    Kosec, P.; Pinto, C.; Walton, D. J.; Fabian, A. C.; Bachetti, M.; Fürst, F.; Grefenstette, B. W.
    Ultraluminous pulsars are a definite proof that persistent super-Eddington accretion occurs in nature. They support the scenario according to which most Ultraluminous X-ray Sources (ULXs) are super-Eddington accretors of stellar mass rather than sub-Eddington intermediate mass black holes. An important prediction of theories of supercritical accretion is the existence of powerful outflows of moderately ionized gas at mildly relativistic speeds. In practice, the spectral resolution of X-ray gratings such as RGS onboard XMM-Newton is required to resolve their observational signatures in ULXs. Using RGS, outflows have been discovered in the spectra of 3 ULXs (none of which are currently known to be pulsars). Most recently, the fourth ultraluminous pulsar...

  20. Alternative Explanations for Extreme Supersolar Iron Abundances Inferred from the Energy Spectrum of Cygnus X-1

    Tomsick, John A.; Parker, Michael L.; García, Javier A.; Yamaoka, Kazutaka; Barret, Didier; Chiu, Jeng-Lun; Clavel, Maïca; Fabian, Andrew; Fürst, Felix; Gandhi, Poshak; Grinberg, Victoria; Miller, Jon M.; Pottschmidt, Katja; Walton, Dominic J.
    Here we study a 1–200 keV energy spectrum of the black hole binary Cygnus X-1 taken with NuSTAR and Suzaku. This is the first report of a NuSTAR observation of Cyg X-1 in the intermediate state, and the observation was taken during the part of the binary orbit where absorption due to the companion's stellar wind is minimal. The spectrum includes a multi-temperature thermal disk component, a cutoff power-law component, and relativistic and nonrelativistic reflection components. Our initial fits with publicly available constant density reflection models (relxill and reflionx) lead to extremely high iron abundances (>9.96 and 10.6_(-0.9)^(+1.6) times solar,...

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