THE ACCRETION DISK CORONA AND DISK ATMOSPHERE OF 4U 1624–490 AS VIEWED BY THE CHANDRA-HIGH ENERGY TRANSMISSION GRATING SPECTROMETER
We present a detailed spectral study (photoionization modeling and variability) of the "Big Dipper" 4U 1624–490 based on a Chandra-High Energy Transmission Grating Spectrometer (HETGS) observation over the ~76 ks binary orbit of 4U 1624–490 . While the continuum spectrum can be modeled us...
| Main Authors: | , , , , |
|---|---|
| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
Institute of Physics/American Astronomical Society
2015
|
| Online Access: | http://hdl.handle.net/1721.1/96086 |
| _version_ | 1826215118840528896 |
|---|---|
| author | Xiang, Jingen Lee, Julia C. Nowak, Michael A. Wilms, Jörn Schulz, Norbert S. |
| author2 | MIT Kavli Institute for Astrophysics and Space Research |
| author_facet | MIT Kavli Institute for Astrophysics and Space Research Xiang, Jingen Lee, Julia C. Nowak, Michael A. Wilms, Jörn Schulz, Norbert S. |
| author_sort | Xiang, Jingen |
| collection | MIT |
| description | We present a detailed spectral study (photoionization modeling and variability) of the "Big Dipper" 4U 1624–490 based on a Chandra-High Energy Transmission Grating Spectrometer (HETGS) observation over the ~76 ks binary orbit of 4U 1624–490 . While the continuum spectrum can be modeled using a blackbody plus power law, a slightly better fit is obtained using a single Γ = 2.25 power-law partially (71%) covered by a local absorber of column density [superscript N]H, Local = 8.1 [+0.7/-0.6] x 10[superscript 22]cm[superscript -2]. The data show a possible quasi-sinusoidal modulation with period 43[superscript +13][subscript –9] ks that might be due to changes in local obscuration. Photoionization modeling with the XSTAR code and variability studies of the observed strong Fe XXV and Fe XXVI absorption lines point to a two-temperature plasma for their origin: a highly ionized component of ionization parameter ξhot ≈ 10[superscript 4.3] erg cm s[superscript -1] (T ~ 3.0 × 10[superscript 6] K) associated with an extended accretion disk corona of radius R ~ 3 × 10[superscript 10] cm, and a less-ionized more variable component of ξ ≈ 103.4 erg cm s-1 (T ~ 1.0 × 106 K) and ξ ≈ 10[superscript 3.1] erg cm s[superscript -1] (T ~ 0.9 × 106 K) coincident with the accretion disk rim. We use this, with the observed Fe XXV and Fe XXVI absorption line variations (in wavelength, strength, and width) to construct a viewing geometry that is mapped to changes in plasma conditions over the 4U 1624–490 orbital period. |
| first_indexed | 2024-09-23T16:17:11Z |
| format | Article |
| id | mit-1721.1/96086 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T16:17:11Z |
| publishDate | 2015 |
| publisher | Institute of Physics/American Astronomical Society |
| record_format | dspace |
| spelling | mit-1721.1/960862022-09-29T19:21:15Z THE ACCRETION DISK CORONA AND DISK ATMOSPHERE OF 4U 1624–490 AS VIEWED BY THE CHANDRA-HIGH ENERGY TRANSMISSION GRATING SPECTROMETER Xiang, Jingen Lee, Julia C. Nowak, Michael A. Wilms, Jörn Schulz, Norbert S. MIT Kavli Institute for Astrophysics and Space Research Nowak, Michael A. Schulz, Norbert S. We present a detailed spectral study (photoionization modeling and variability) of the "Big Dipper" 4U 1624–490 based on a Chandra-High Energy Transmission Grating Spectrometer (HETGS) observation over the ~76 ks binary orbit of 4U 1624–490 . While the continuum spectrum can be modeled using a blackbody plus power law, a slightly better fit is obtained using a single Γ = 2.25 power-law partially (71%) covered by a local absorber of column density [superscript N]H, Local = 8.1 [+0.7/-0.6] x 10[superscript 22]cm[superscript -2]. The data show a possible quasi-sinusoidal modulation with period 43[superscript +13][subscript –9] ks that might be due to changes in local obscuration. Photoionization modeling with the XSTAR code and variability studies of the observed strong Fe XXV and Fe XXVI absorption lines point to a two-temperature plasma for their origin: a highly ionized component of ionization parameter ξhot ≈ 10[superscript 4.3] erg cm s[superscript -1] (T ~ 3.0 × 10[superscript 6] K) associated with an extended accretion disk corona of radius R ~ 3 × 10[superscript 10] cm, and a less-ionized more variable component of ξ ≈ 103.4 erg cm s-1 (T ~ 1.0 × 106 K) and ξ ≈ 10[superscript 3.1] erg cm s[superscript -1] (T ~ 0.9 × 106 K) coincident with the accretion disk rim. We use this, with the observed Fe XXV and Fe XXVI absorption line variations (in wavelength, strength, and width) to construct a viewing geometry that is mapped to changes in plasma conditions over the 4U 1624–490 orbital period. Harvard University (Faculty of Arts and Sciences funding) United States. National Aeronautics and Space Administration (NASA/Chandra grant GO4-3056X) 2015-03-19T18:23:33Z 2015-03-19T18:23:33Z 2009-08 2008-12 Article http://purl.org/eprint/type/JournalArticle 0004-637X 1538-4357 http://hdl.handle.net/1721.1/96086 Xiang, Jingen, Julia C. Lee, Michael A. Nowak, Jörn Wilms, and Norbert S. Schulz. “ THE ACCRETION DISK CORONA AND DISK ATMOSPHERE OF 4U 1624–490 AS VIEWED BY THE CHANDRA -HIGH ENERGY TRANSMISSION GRATING SPECTROMETER .” The Astrophysical Journal 701, no. 2 (July 29, 2009): 984–993. © 2009 American Astronomical Society. en_US http://dx.doi.org/10.1088/0004-637x/701/2/984 Astrophysical Journal Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Institute of Physics/American Astronomical Society American Astronomical Society |
| spellingShingle | Xiang, Jingen Lee, Julia C. Nowak, Michael A. Wilms, Jörn Schulz, Norbert S. THE ACCRETION DISK CORONA AND DISK ATMOSPHERE OF 4U 1624–490 AS VIEWED BY THE CHANDRA-HIGH ENERGY TRANSMISSION GRATING SPECTROMETER |
| title | THE ACCRETION DISK CORONA AND DISK ATMOSPHERE OF 4U 1624–490 AS VIEWED BY THE CHANDRA-HIGH ENERGY TRANSMISSION GRATING SPECTROMETER |
| title_full | THE ACCRETION DISK CORONA AND DISK ATMOSPHERE OF 4U 1624–490 AS VIEWED BY THE CHANDRA-HIGH ENERGY TRANSMISSION GRATING SPECTROMETER |
| title_fullStr | THE ACCRETION DISK CORONA AND DISK ATMOSPHERE OF 4U 1624–490 AS VIEWED BY THE CHANDRA-HIGH ENERGY TRANSMISSION GRATING SPECTROMETER |
| title_full_unstemmed | THE ACCRETION DISK CORONA AND DISK ATMOSPHERE OF 4U 1624–490 AS VIEWED BY THE CHANDRA-HIGH ENERGY TRANSMISSION GRATING SPECTROMETER |
| title_short | THE ACCRETION DISK CORONA AND DISK ATMOSPHERE OF 4U 1624–490 AS VIEWED BY THE CHANDRA-HIGH ENERGY TRANSMISSION GRATING SPECTROMETER |
| title_sort | accretion disk corona and disk atmosphere of 4u 1624 490 as viewed by the chandra high energy transmission grating spectrometer |
| url | http://hdl.handle.net/1721.1/96086 |
| work_keys_str_mv | AT xiangjingen theaccretiondiskcoronaanddiskatmosphereof4u1624490asviewedbythechandrahighenergytransmissiongratingspectrometer AT leejuliac theaccretiondiskcoronaanddiskatmosphereof4u1624490asviewedbythechandrahighenergytransmissiongratingspectrometer AT nowakmichaela theaccretiondiskcoronaanddiskatmosphereof4u1624490asviewedbythechandrahighenergytransmissiongratingspectrometer AT wilmsjorn theaccretiondiskcoronaanddiskatmosphereof4u1624490asviewedbythechandrahighenergytransmissiongratingspectrometer AT schulznorberts theaccretiondiskcoronaanddiskatmosphereof4u1624490asviewedbythechandrahighenergytransmissiongratingspectrometer AT xiangjingen accretiondiskcoronaanddiskatmosphereof4u1624490asviewedbythechandrahighenergytransmissiongratingspectrometer AT leejuliac accretiondiskcoronaanddiskatmosphereof4u1624490asviewedbythechandrahighenergytransmissiongratingspectrometer AT nowakmichaela accretiondiskcoronaanddiskatmosphereof4u1624490asviewedbythechandrahighenergytransmissiongratingspectrometer AT wilmsjorn accretiondiskcoronaanddiskatmosphereof4u1624490asviewedbythechandrahighenergytransmissiongratingspectrometer AT schulznorberts accretiondiskcoronaanddiskatmosphereof4u1624490asviewedbythechandrahighenergytransmissiongratingspectrometer |