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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"

20964 results found.

  1. GRB 241215A: Montarrenti Observatory optical upper limit
  2. Integral GRB241215.58: Global MASTER-Net observations report
  3. GRB 241213B: Swift-XRT observations
  4. GRB 241213A: SVOM/VT optical candidate
  5. GRB 241213B: Tiled Swift observations
  6. GRB 241213A: Swift/UVOT Upper Limits
  7. EP241208a: NOT optical upper limits
  8. GRB 241212A: Swift ToO observations
  9. EP241213a/GRB241213a: Likely joint detection and INTEGRAL/SPI-ACS counterpart
  10. GRB 241213A: REM optical/NIR upper limits
  11. GRB241212A: OHP/T193 optical observations
  12. GRB 241213A: SAO RAS optical upper limit
  13. Swift GRB 241213A: Global MASTER-Net observations report
  14. GRB 241212A : SVOM/VT bright optical afterglow
  15. GRB 241209B: GRANDMA/TRT upper limit
  16. GRB 241207A: TSHAO Zeiss-1000 optical observations
  17. GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations
  18. GRB 241209A: Chandra X-ray Detection
  19. GRB 241209D: REM optical/NIR upper limits
  20. GRB 241209B: Swift-XRT afterglow detection
  21. EP241208a: Optical upper limit with Kinder observations
  22. GRB 241128A: CrAO ZTSh and Mondy AZT-33IK optical observations
  23. GRB 241209A: EP-FXT follow-up observations
  24. GRB 241209B: SVOM/VT afterglow detection
  25. EP241208a: Global MASTER-Net observations report
  26. EP241208a: EP-FXT follow-up observations
  27. Fermi trigger No 755485387: Global MASTER-Net observations report
  28. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  29. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  30. GRB 241209D: COLIBRÍ detection of the afterglow
  31. GRB 241209A: COLIBRÍ Optical Upper Limit
  32. Fermi GRB 241209D: Global MASTER-Net observations report
  33. GRB 241209A: Fermi GBM Observation
  34. GRB 241209A: GRANDMA/TAROT upper limit
  35. Swift GRB 241209D: Global MASTER-Net observations report
  36. Fermi GRB 241209C: Global MASTER-Net observations report
  37. Fermi GRB 241209E: Global MASTER-Net observations report
  38. GRB 241209B: Swift ToO observations
  39. LIGO/Virgo/KAGRA S241102br: continued GRAWITA observations and detection of an optical transient (AT2024adip)
  40. GRB 241209A: REM optical/NIR observations
  41. GRB 241209A: VLT/X-shooter spectroscopy
  42. GRB 241209A: VLT optical observations
  43. Fermi GRB 241209A: Global MASTER-Net observations report
  44. GRB 241209A: GOTO optical upper limits
  45. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  46. EP241208a: EP detection of a fast X-ray transient
  47. Swift GRB241209.23: Global MASTER-Net observations report
  48. Fermi GRB 241207B: Global MASTER-Net observations report
  49. GRB 241206A: DDOTI Upper Limit on the Afterglow
  50. AT2024adec: X-ray Upper Limits from EP-FXT Observation
  51. EP241206a: BOOTES Global Network optical limits
  52. GRB 241207C: MASTER optical observations
  53. Fermi trigger No 755225799: Global MASTER-Net observations report
  54. GRB 241207C: Tiled Swift observations
  55. Fermi trigger No 755277791: Global MASTER-Net observations report
  56. Fermi GRB 241207A: Global MASTER-Net observations report
  57. EP241206a: Global MASTER-Net observations report
  58. EP241206a: EP detection of a fast X-ray transient
  59. GRB 241206B: SVOM/MXT observations: a probable flare from the QSO 1ES 1959+650
  60. EP241113a: Keck/LRIS spectroscopic observation and tentative redshift
  61. Fermi GRB 241206A: Global MASTER-Net observations report
  62. GRB 241204A: COLIBRÍ Optical Upper Limit
  63. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  64. GRB 241204A: DDOTI Upper Limits on the Afterglow
  65. Fermi GRB 241204A: Global MASTER-Net observations report
  66. GRB 241128A : RAPAS follow-up observations
  67. EP241202b: Upper limits from Fermi-GBM Observations
  68. IceCube-241127A: No transient candidates from the Zwicky Transient Facility
  69. EP241202b: Kinder optical counterpart candidate
  70. EP241201a: EP-FXT follow-up observations
  71. EP241202b: Global MASTER-Net observations report
  72. EP241202b: EP detection of a fast X-ray transient
  73. EP241201a: NOT optical observations
  74. GRB 241128A: Swift/UVOT Upper Limits
  75. EP241201a: Kinder optical counterpart candidate
  76. LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
  77. EP241201a: Global MASTER-Net observations report
  78. EP241201a: EP detection of a fast X-ray transient
  79. EP241126a: SOAR observations of the optical counterpart
  80. Fermi GRB 241201A: Global MASTER-Net observations report
  81. EP241126a: 1.6m Mephisto Optical Upper Limits
  82. Fermi trigger No 754701230: Global MASTER-Net observations report
  83. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  84. EP241126a: NOT optical observations
  85. GRB 241127A: PRIME near-infrared detection
  86. GRB 241128A: Mondy optical observations
  87. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  88. Swift-XRT observations of IceCube -241127A
  89. Swift GRB 241128A: Global MASTER-Net observations report
  90. Fermi-LAT gamma-ray observations of IceCube-241127A
  91. EP241126a: SVOM/VT observations
  92. GRB 241128A: NOT optical observations
  93. GRB 241128A: LCO optical detection
  94. GRB 241128A: 1.5m OSN optical afterglow detection
  95. LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
  96. Fermi trigger No 754492985: Global MASTER-Net observations report
  97. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  98. GRB 241127A: Swift/UVOT Detection
  99. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  100. EP241126a: WFST Observations

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