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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"

32692 results found.

  1. The EP-WXT trigger 01709131085: KAIT confirmation of the stellar flare
  2. GRB 250128B: TNG optical upper limit
  3. GRB 250129A: Swift/UVOT Detection
  4. GRB 250128B: VLT/HAWKI near-infrared observations
  5. GRB 250127A: CrAO and Terskol optical upper limits
  6. GRB 250128B: NOT optical upper limit
  7. GRB 250128B: VLT/FORS2 optical observations
  8. GRB 250129A: REM optical/NIR afterglow detection
  9. GRB 250129A: OHP/T193 optical and spectroscopy observations
  10. GRB 250129A: Early afterglow detection by LCO.
  11. GRB 250128B: OHP/T193 optical upper limit
  12. Swift GRB 250129A: Global MASTER-Net Slowly evolving LC detection
  13. GRB 250129A: LCO optical observations
  14. GRB 250129A: NOT optical observations and redshift confirmation
  15. GRB 250129A: GOTO optical observations show brightening afterglow
  16. GRB 250129A: VLT/X-shooter redshift of z = 2.151
  17. Swift GRB 250129A: Global MASTER-Net observations report
  18. Fermi GRB 250128B: Global MASTER-Net observations report
  19. GRB 250128B: Fermi GBM Observation
  20. GRB 250128B: GOTO optical upper limit
  21. Swift GRB 250128B: Global MASTER-Net observations report
  22. EP250125a: Upper limits from Swift/BAT-GUANO
  23. GRB 250128B: LCO optical observations
  24. GRB 250127A: Swift-XRT observations
  25. GRB 250127B: DDOTI Upper Limit on the Afterglow
  26. Fermi-LAT Gamma-ray Observations of IceCube-250102A
  27. GRB 250127A: EP-FXT afterglow detection
  28. Fermi GRB 250128A: Global MASTER-Net observations report
  29. GRB 250117A: Fermi GBM Observation
  30. Fermi GRB 250127B: Global MASTER-Net observations report
  31. Fermi-LAT Gamma-ray Observations of IceCube-250101A
  32. GRB 250127A: SVOM/VT upper limit
  33. IPN triangulation of GRB 250119C
  34. GRB 250127A: Swift ToO observations
  35. GRB 250127A: LCO optical upper limit
  36. GRB 241223A: cubesat Avion detection
  37. GRB 250126A: CALET Gamma-Ray Burst Monitor detection
  38. EP250125A: Non-detection from Fermi-GBM Observations
  39. GRB 250126A: MAXI/GSC detection
  40. EP250108a / SN 2025kg: Refined Analysis of EP-WXT Detection
  41. GECAM-A detection of a bright burst from SGR 1E1841-045
  42. GRB 250118A: Fermi GBM Observation
  43. EP250125a: Optical upper limit with Kinder observations
  44. EP250125a: REM optical counterpart detection
  45. GRB 250119C: Fermi GBM Observation
  46. EP250125a: Swift/XRT detection of a fading counterpart
  47. EP250125a: a new X-ray transient detected by Einstein Probe
  48. Konus-Wind detection of a bright burst from SGR 1E1841-045 on 2025 January 23
  49. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  50. IPN triangulation of a bright burst from SGR 1E1841-045
  51. GRB 250121A: CALET Gamma-Ray Burst Monitor detection
  52. EP250108a: AbAO, CMO and Terskol optical upper limits
  53. Konus-Wind detection of GRB 250118B
  54. GRB 250121A: Fermi GBM Observation
  55. IPN triangulation of GRB 250118B
  56. Konus-Wind detection of GRB 250119B
  57. IPN triangulation of GRB 250119B
  58. Improved IPN triangulation of GRB 250107C
  59. GRB 250114A: Swift-BAT refined analysis
  60. GRB 250121A: INTEGRAL/SPI-ACS detection
  61. GRB 250121A: Fermi-LAT detection
  62. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  63. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  64. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  65. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  66. GRB 250119B: Fermi GBM Observation
  67. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  68. Konus-Wind detection of GRB 250117A
  69. IPN triangulation of GRB 250117A (short)
  70. ATCA detection of possible radio counterpart to GRB 250114A
  71. EP250108a / SN2025kg: Non-detection from ATCA radio follow-up observations
  72. GRB 250119B: INTEGRAL/SPI-ACS detection
  73. LIGO/Virgo/KAGRA S250119cv: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  74. EP 250108A: Late-time optical observation by LCO
  75. GRB 250117A: SVOM/GRM observation of a short burst
  76. LIGO/Virgo/KAGRA S250119cv: Updated Sky localization and EM Bright Classification
  77. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  78. EP250108a / SN2025kg: Gemini GMOS-S confirmation of an associated broad-lined SN Ic
  79. LIGO/Virgo/KAGRA S250119cv: Identification of a GW compact binary merger candidate
  80. LIGO/Virgo/KAGRA S250119ag: Updated Sky localization
  81. EP250108a/AT 2025kg: NOT spectroscopy in agreement with SN Ic-BL
  82. EP250108a / AT 2025kg: the kangaroo is hopping, evidence for optical rebrightening
  83. GRB 250117A: GECAM observation of a short burst
  84. LIGO/Virgo/KAGRA S250118dp: Updated Sky localization
  85. LIGO/Virgo/KAGRA S250119ag: Identification of a GW compact binary merger candidate
  86. LIGO/Virgo/KAGRA S250118dp: Identification of a GW compact binary merger candidate
  87. LIGO/Virgo/KAGRA S250118t: Updated Sky localization
  88. LIGO/Virgo/KAGRA S250118az: Identification of a GW compact binary merger candidate
  89. EP250108a / AT2025kg: GMG Optical Observations
  90. LIGO/Virgo/KAGRA S250118t: Identification of a GW compact binary merger candidate
  91. EP250108a / AT2025kg: VLA radio upper limit
  92. Konus-Wind detection of GRB 250116A
  93. GRB 250116A: GECAM-B detection of a long burst
  94. GRB 241217A / EP241217B: radio detection with the VLA
  95. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  96. GRB 250116A: Fermi-LAT detection
  97. GRB 250114B: Swift-XRT afterglow detection
  98. GRB 250114B: SVOM/VT upper limit
  99. EP250108a: MeerKAT radio upper limit
  100. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.

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