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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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').
Advanced Search

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.

Advanced Search Examples (click to copy):

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

11841 results found.

  1. GRB 241217a/EP241217b: ATCA Radio Detection
  2. EP241217a: VLA Radio Detection

  3. LIGO/Virgo/KAGRA S241231du: Coverage and upper limit from MAXI/GSC observations
  4. LIGO/Virgo/KAGRA S241231bg: Updated NED Galaxies in the Localization Volume
  5. LIGO/Virgo/KAGRA S241231bg: NED Galaxies in the Localization Volume
  6. GRB 241229A: EP-FXT X-ray afterglow confirmation
  7. EP241217A: J band upper limit by SYSU 80cm telescope
  8. GRB 241229B: CrAO ZTSh possible optical counterpart of SVOM/VT confirmation
  9. Konus-Wind detection of GRB 241228A
  10. EP240702a: 7DT Optical upper limits
  11. GRB 240606B: 7DT Optical upper limits
  12. GRB 241228B: Swift-XRT afterglow detection
  13. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  14. Fermi GRB 241228B: Global MASTER-Net observations report
  15. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  16. GRB 241228A: Swift-XRT refined Analysis
  17. GRB 241228A: Swift detection of a burst
  18. GRB 241217A/EP241217b: continued SOAR observations
  19. Fermi GRB 241226A: Global MASTER-Net observations report
  20. Fermi trigger No 756678579: Global MASTER-Net observations report
  21. IceCube Alert 241224.30: Global MASTER-Net observations report
  22. EP241223a: Global MASTER-Net observations report
  23. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  24. GRB241113A: 7DT Optical upper limits
  25. Fermi Gamma-ray Burst Monitor trigger 756678579 / 241223854 is not a GRB
  26. Fermi GRB 241223A: Global MASTER-Net observations report
  27. GRB 241223A: GOTO optical observations summary
  28. EP241217a: e-MERLIN radio observations
  29. GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
  30. Fermi trigger No 756447119: Global MASTER-Net observations report
  31. GRB 241217A/EP241217b: SOAR afterglow detection
  32. EP241217a: Liverpool Telescope optical upper limit
  33. GRB 241218A: Mondy AZT-33IK optical upper limit
  34. Konus-Wind detection of GRB 241204A (short/hard)
  35. EP 241217a: NIR detection with P200/WIRC
  36. GRB 241217A / EP241217b: NOT optical upper limits
  37. GRB 241218A: Swift-XRT refined Analysis
  38. EP241119a: 7DT Optical upper limits
  39. EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
  40. EP241217a: Global MASTER-Net observations report
  41. GRB 241218A: Swift detection of a burst
  42. EP241217a: Swift-XRT Detection
  43. EP241217a: EP detection of an X-ray transient
  44. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  45. Konus-Wind detection of GRB 241213A (EP 241213a)
  46. The EP-WXT trigger 01709128948 is likely a flaring star
  47. GRB 241215A: A long GRB detected by INTEGRAL
  48. GRB 241213A: Swift-XRT refined Analysis
  49. EP 241208A : Detection of a long soft transient by SVOM/ECLAIRs
  50. GRB 241213B: MAXI/GSC detection
  51. GRB 241213A: Swift detection of a burst
  52. GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations
  53. Konus-Wind detection of GRB 241209B
  54. GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
  55. Konus-Wind detection of GRB 241209D
  56. GRB 241209C: Fermi GBM Observation
  57. GRB 241209A: Swift-XRT refined Analysis
  58. GRB 241209A: EP-FXT follow-up observations
  59. EP241208a: Global MASTER-Net observations report
  60. EP241208a: EP-FXT follow-up observations
  61. Fermi trigger No 755485387: Global MASTER-Net observations report
  62. GRB 241207B: Fermi GBM Observation
  63. GRB 241209D: Swift-XRT refined Analysis
  64. GRB 241209D: COLIBRÍ detection of the afterglow
  65. Fermi GRB 241209D: Global MASTER-Net observations report
  66. GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
  67. Swift GRB 241209D: Global MASTER-Net observations report
  68. Fermi GRB 241209A: Global MASTER-Net observations report
  69. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  70. EP241208a: EP detection of a fast X-ray transient
  71. GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
  72. Fermi Gamma-ray Burst Monitor trigger 755277791/241207641 is not a GRB
  73. AT2024adec: X-ray Upper Limits from EP-FXT Observation
  74. GRB 241207C: MAXI/GSC detection
  75. GRB 241207B: Fermi GBM Final Real-time Localization
  76. Fermi GRB 241207A: Global MASTER-Net observations report
  77. EP241206a: Global MASTER-Net observations report
  78. EP241206a: EP detection of a fast X-ray transient
  79. GRB 241206A: Fermi GBM observation
  80. GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
  81. EP241113a: Keck/LRIS spectroscopic observation and tentative redshift
  82. Fermi GRB 241206A: Global MASTER-Net observations report
  83. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  84. GRB 241204A: Fermi-LAT detection
  85. IceCube-241127A: No transient candidates from the Zwicky Transient Facility
  86. Konus-Wind detection of GRB 241130A
  87. EP241201a: BOOTES-5 optical upper limit
  88. EP241202b: EP detection of a fast X-ray transient
  89. GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
  90. EP241201a: Global MASTER-Net observations report
  91. GRB 241127B: detection of a long GRB by SVOM/ECLAIRs
  92. Fermi trigger No 754701230: Global MASTER-Net observations report
  93. Konus-Wind detection of GRB 241114B
  94. LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
  95. Fermi-LAT gamma-ray observations of IceCube-241127A
  96. LIGO/Virgo/KAGRA S241129aa: Identification of a GW compact binary merger candidate
  97. GRB 241128A: Swift-XRT refined Analysis
  98. LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
  99. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  100. GRB 241127A: Swift-XRT refined Analysis

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