The Density and Ionization Profiles of Optically Dark and High-Redshift GRBs Probed by X-ray Absorption
The X-ray column density (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>N</mi><mi>HX</mi></msub></semantics></math></inline-formula>) of gamma-ray burs...
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2024-08-01
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| author | Eka Puspita Arumaningtyas Hasan Al Rasyid Maria Giovanna Dainotti Daisuke Yonetoku |
| author_facet | Eka Puspita Arumaningtyas Hasan Al Rasyid Maria Giovanna Dainotti Daisuke Yonetoku |
| author_sort | Eka Puspita Arumaningtyas |
| collection | DOAJ |
| description | The X-ray column density (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>N</mi><mi>HX</mi></msub></semantics></math></inline-formula>) of gamma-ray bursts (GRBs) can probe the local environment of their progenitors over a wide redshift range. Previous work has suggested an increasing trend as a function of redshift. The relevance of this current analysis relies on investigating the selection bias method, such as the effect of the X-ray spectrum in high-redshift GRBs, which complicates the measurement of small <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>N</mi><mi>HX</mi></msub></semantics></math></inline-formula>; this has yet to be fully evaluated or discussed elsewhere. In this work, we evaluated these effects through simulations to define appropriate observational limits in the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>N</mi><mi>HX</mi></msub></semantics></math></inline-formula> versus redshift plane. We then applied a one-sided nonparametric method developed by Efron and Petrosian. Within the framework of this method, we investigated the redshift dependence of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>N</mi><mi>HX</mi></msub></semantics></math></inline-formula> and the local distribution function. Our results show that the evolution of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>N</mi><mi>HX</mi></msub></semantics></math></inline-formula> with redshift firmly exists with a significance of more than four sigma and follows a power law of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow><mo>(</mo><mn>1</mn><mo>+</mo><mi>z</mi><mo>)</mo></mrow><mrow><mn>1.39</mn><mo>(</mo><mo>+</mo><mn>0.22</mn><mo>,</mo><mo>−</mo><mn>0.27</mn><mo>)</mo></mrow></msup></semantics></math></inline-formula>. Based on these analyses and previous studies, the GRB progenitor mass varies but is more massive in the high-redshift environment and has a higher gas column density. This suggests that part of the luminosity evolution of GRBs, which has been widely reported, may be due to the evolution of the progenitor’s mass. Using the same method, we demonstrate that optically dark GRBs show a consistent evolution: <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow><mo>(</mo><mn>1</mn><mo>+</mo><mi>z</mi><mo>)</mo></mrow><mrow><mn>1.15</mn><mo>(</mo><mo>+</mo><mn>0.67</mn><mo>,</mo><mo>−</mo><mn>0.83</mn><mo>)</mo></mrow></msup></semantics></math></inline-formula>. By applying the Kolmogorov–Smirnov (KS) test, it is shown that optically dark GRBs have statistically identical flux and photon index distributions compared to normal GRBs, but the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>N</mi><mi>HX</mi></msub></semantics></math></inline-formula> is systematically larger. This result suggests that the darkness of some GRB populations is not due to an intrinsic mechanism, but rather because a higher density surrounds them. |
| format | Article |
| id | doaj-art-47c141e36de24f62a6889c0104f82996 |
| institution | OA Journals |
| issn | 2075-4434 |
| language | English |
| publishDate | 2024-08-01 |
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| series | Galaxies |
| spelling | doaj-art-47c141e36de24f62a6889c0104f829962025-08-20T02:11:05ZengMDPI AGGalaxies2075-44342024-08-011255110.3390/galaxies12050051The Density and Ionization Profiles of Optically Dark and High-Redshift GRBs Probed by X-ray AbsorptionEka Puspita Arumaningtyas0Hasan Al Rasyid1Maria Giovanna Dainotti2Daisuke Yonetoku3Faculty of Mathematics and Physics, Kanazawa University, Kakumamachi, Kanazawa 920-1192, Ishikawa, JapanFaculty of Engineering, Nurul Jadid University, Paiton, Probolinggo 67291, IndonesiaDivision of Science, National Astronomical Observatory of Japan, Osawa, Mitaka 181-8588, Tokyo, JapanFaculty of Mathematics and Physics, Kanazawa University, Kakumamachi, Kanazawa 920-1192, Ishikawa, JapanThe X-ray column density (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>N</mi><mi>HX</mi></msub></semantics></math></inline-formula>) of gamma-ray bursts (GRBs) can probe the local environment of their progenitors over a wide redshift range. Previous work has suggested an increasing trend as a function of redshift. The relevance of this current analysis relies on investigating the selection bias method, such as the effect of the X-ray spectrum in high-redshift GRBs, which complicates the measurement of small <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>N</mi><mi>HX</mi></msub></semantics></math></inline-formula>; this has yet to be fully evaluated or discussed elsewhere. In this work, we evaluated these effects through simulations to define appropriate observational limits in the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>N</mi><mi>HX</mi></msub></semantics></math></inline-formula> versus redshift plane. We then applied a one-sided nonparametric method developed by Efron and Petrosian. Within the framework of this method, we investigated the redshift dependence of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>N</mi><mi>HX</mi></msub></semantics></math></inline-formula> and the local distribution function. Our results show that the evolution of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>N</mi><mi>HX</mi></msub></semantics></math></inline-formula> with redshift firmly exists with a significance of more than four sigma and follows a power law of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow><mo>(</mo><mn>1</mn><mo>+</mo><mi>z</mi><mo>)</mo></mrow><mrow><mn>1.39</mn><mo>(</mo><mo>+</mo><mn>0.22</mn><mo>,</mo><mo>−</mo><mn>0.27</mn><mo>)</mo></mrow></msup></semantics></math></inline-formula>. Based on these analyses and previous studies, the GRB progenitor mass varies but is more massive in the high-redshift environment and has a higher gas column density. This suggests that part of the luminosity evolution of GRBs, which has been widely reported, may be due to the evolution of the progenitor’s mass. Using the same method, we demonstrate that optically dark GRBs show a consistent evolution: <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow><mo>(</mo><mn>1</mn><mo>+</mo><mi>z</mi><mo>)</mo></mrow><mrow><mn>1.15</mn><mo>(</mo><mo>+</mo><mn>0.67</mn><mo>,</mo><mo>−</mo><mn>0.83</mn><mo>)</mo></mrow></msup></semantics></math></inline-formula>. By applying the Kolmogorov–Smirnov (KS) test, it is shown that optically dark GRBs have statistically identical flux and photon index distributions compared to normal GRBs, but the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>N</mi><mi>HX</mi></msub></semantics></math></inline-formula> is systematically larger. This result suggests that the darkness of some GRB populations is not due to an intrinsic mechanism, but rather because a higher density surrounds them.https://www.mdpi.com/2075-4434/12/5/51absorption materialintergalactic mediumgamma ray burstLyman-alphaearly universe |
| spellingShingle | Eka Puspita Arumaningtyas Hasan Al Rasyid Maria Giovanna Dainotti Daisuke Yonetoku The Density and Ionization Profiles of Optically Dark and High-Redshift GRBs Probed by X-ray Absorption Galaxies absorption material intergalactic medium gamma ray burst Lyman-alpha early universe |
| title | The Density and Ionization Profiles of Optically Dark and High-Redshift GRBs Probed by X-ray Absorption |
| title_full | The Density and Ionization Profiles of Optically Dark and High-Redshift GRBs Probed by X-ray Absorption |
| title_fullStr | The Density and Ionization Profiles of Optically Dark and High-Redshift GRBs Probed by X-ray Absorption |
| title_full_unstemmed | The Density and Ionization Profiles of Optically Dark and High-Redshift GRBs Probed by X-ray Absorption |
| title_short | The Density and Ionization Profiles of Optically Dark and High-Redshift GRBs Probed by X-ray Absorption |
| title_sort | density and ionization profiles of optically dark and high redshift grbs probed by x ray absorption |
| topic | absorption material intergalactic medium gamma ray burst Lyman-alpha early universe |
| url | https://www.mdpi.com/2075-4434/12/5/51 |
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