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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

32688 results found.

  1. GRB 250127A: CrAO and Terskol optical upper limits
  2. GRB 250128B: NOT optical upper limit
  3. GRB 250128B: VLT/FORS2 optical observations
  4. GRB 250129A: REM optical/NIR afterglow detection
  5. GRB 250129A: OHP/T193 optical and spectroscopy observations
  6. GRB 250129A: Early afterglow detection by LCO.
  7. GRB 250128B: OHP/T193 optical upper limit
  8. Swift GRB 250129A: Global MASTER-Net Slowly evolving LC detection
  9. GRB 250129A: LCO optical observations
  10. GRB 250129A: NOT optical observations and redshift confirmation
  11. GRB 250129A: GOTO optical observations show brightening afterglow
  12. GRB 250129A: VLT/X-shooter redshift of z = 2.151
  13. Swift GRB 250129A: Global MASTER-Net observations report
  14. Fermi GRB 250128B: Global MASTER-Net observations report
  15. GRB 250128B: Fermi GBM Observation
  16. GRB 250128B: GOTO optical upper limit
  17. Swift GRB 250128B: Global MASTER-Net observations report
  18. EP250125a: Upper limits from Swift/BAT-GUANO
  19. GRB 250128B: LCO optical observations
  20. GRB 250127A: Swift-XRT observations
  21. GRB 250127B: DDOTI Upper Limit on the Afterglow
  22. Fermi-LAT Gamma-ray Observations of IceCube-250102A
  23. GRB 250127A: EP-FXT afterglow detection
  24. Fermi GRB 250128A: Global MASTER-Net observations report
  25. GRB 250117A: Fermi GBM Observation
  26. Fermi GRB 250127B: Global MASTER-Net observations report
  27. Fermi-LAT Gamma-ray Observations of IceCube-250101A
  28. GRB 250127A: SVOM/VT upper limit
  29. IPN triangulation of GRB 250119C
  30. GRB 250127A: Swift ToO observations
  31. GRB 250127A: LCO optical upper limit
  32. GRB 241223A: cubesat Avion detection
  33. GRB 250126A: CALET Gamma-Ray Burst Monitor detection
  34. EP250125A: Non-detection from Fermi-GBM Observations
  35. GRB 250126A: MAXI/GSC detection
  36. EP250108a / SN 2025kg: Refined Analysis of EP-WXT Detection
  37. GECAM-A detection of a bright burst from SGR 1E1841-045
  38. GRB 250118A: Fermi GBM Observation
  39. EP250125a: Optical upper limit with Kinder observations
  40. EP250125a: REM optical counterpart detection
  41. GRB 250119C: Fermi GBM Observation
  42. EP250125a: Swift/XRT detection of a fading counterpart
  43. EP250125a: a new X-ray transient detected by Einstein Probe
  44. Konus-Wind detection of a bright burst from SGR 1E1841-045 on 2025 January 23
  45. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  46. IPN triangulation of a bright burst from SGR 1E1841-045
  47. GRB 250121A: CALET Gamma-Ray Burst Monitor detection
  48. EP250108a: AbAO, CMO and Terskol optical upper limits
  49. Konus-Wind detection of GRB 250118B
  50. GRB 250121A: Fermi GBM Observation
  51. IPN triangulation of GRB 250118B
  52. Konus-Wind detection of GRB 250119B
  53. IPN triangulation of GRB 250119B
  54. Improved IPN triangulation of GRB 250107C
  55. GRB 250114A: Swift-BAT refined analysis
  56. GRB 250121A: INTEGRAL/SPI-ACS detection
  57. GRB 250121A: Fermi-LAT detection
  58. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  59. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  60. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  61. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  62. GRB 250119B: Fermi GBM Observation
  63. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  64. Konus-Wind detection of GRB 250117A
  65. IPN triangulation of GRB 250117A (short)
  66. ATCA detection of possible radio counterpart to GRB 250114A
  67. EP250108a / SN2025kg: Non-detection from ATCA radio follow-up observations
  68. GRB 250119B: INTEGRAL/SPI-ACS detection
  69. LIGO/Virgo/KAGRA S250119cv: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  70. EP 250108A: Late-time optical observation by LCO
  71. GRB 250117A: SVOM/GRM observation of a short burst
  72. LIGO/Virgo/KAGRA S250119cv: Updated Sky localization and EM Bright Classification
  73. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  74. EP250108a / SN2025kg: Gemini GMOS-S confirmation of an associated broad-lined SN Ic
  75. LIGO/Virgo/KAGRA S250119cv: Identification of a GW compact binary merger candidate
  76. LIGO/Virgo/KAGRA S250119ag: Updated Sky localization
  77. EP250108a/AT 2025kg: NOT spectroscopy in agreement with SN Ic-BL
  78. EP250108a / AT 2025kg: the kangaroo is hopping, evidence for optical rebrightening
  79. GRB 250117A: GECAM observation of a short burst
  80. LIGO/Virgo/KAGRA S250118dp: Updated Sky localization
  81. LIGO/Virgo/KAGRA S250119ag: Identification of a GW compact binary merger candidate
  82. LIGO/Virgo/KAGRA S250118dp: Identification of a GW compact binary merger candidate
  83. LIGO/Virgo/KAGRA S250118t: Updated Sky localization
  84. LIGO/Virgo/KAGRA S250118az: Identification of a GW compact binary merger candidate
  85. EP250108a / AT2025kg: GMG Optical Observations
  86. LIGO/Virgo/KAGRA S250118t: Identification of a GW compact binary merger candidate
  87. EP250108a / AT2025kg: VLA radio upper limit
  88. Konus-Wind detection of GRB 250116A
  89. GRB 250116A: GECAM-B detection of a long burst
  90. GRB 241217A / EP241217B: radio detection with the VLA
  91. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  92. GRB 250116A: Fermi-LAT detection
  93. GRB 250114B: Swift-XRT afterglow detection
  94. GRB 250114B: SVOM/VT upper limit
  95. EP250108a: MeerKAT radio upper limit
  96. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  97. LIGO/Virgo/KAGRA S250114ax: Updated Sky localization
  98. Konus-Wind detection of GRB 250113A
  99. IPN triangulation of GRB 250113A
  100. GRB 250114B: Liverpool Telescope optical upper limit

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