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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').
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"

21970 results found.

  1. EP241217A: LCO optical observations
  2. EP241217a: Gemini-North detection of the likely optical counterpart
  3. EP241217a: EP detection of an X-ray transient
  4. EP241107a: VLA Radio Observation
  5. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  6. GRB 241215A: Mondy AZT-33IK optical observations
  7. GRB 241212A: Swift-XRT observations
  8. GRB 241215A: Nanshan/HMT optical upper limit
  9. GRB 241215A: Montarrenti Observatory optical upper limit
  10. Integral GRB241215.58: Global MASTER-Net observations report
  11. GRB 241213B: Swift-XRT observations
  12. GRB 241213A: SVOM/VT optical candidate
  13. GRB 241213B: Tiled Swift observations
  14. GRB 241213A: Swift/UVOT Upper Limits
  15. EP241208a: NOT optical upper limits
  16. GRB 241212A: Swift ToO observations
  17. EP241213a/GRB241213a: Likely joint detection and INTEGRAL/SPI-ACS counterpart
  18. GRB 241213A: REM optical/NIR upper limits
  19. GRB241212A: OHP/T193 optical observations
  20. GRB 241213A: SAO RAS optical upper limit
  21. Swift GRB 241213A: Global MASTER-Net observations report
  22. GRB 241212A : SVOM/VT bright optical afterglow
  23. GRB 241209B: GRANDMA/TRT upper limit
  24. GRB 241207A: TSHAO Zeiss-1000 optical observations
  25. GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations
  26. GRB 241209A: Chandra X-ray Detection
  27. GRB 241209A: Redshift of the likely host galaxy z = 0.784 from OSIRIS+/GTC
  28. GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
  29. GRB 241209D: REM optical/NIR upper limits
  30. GRB 241209B: Swift-XRT afterglow detection
  31. EP241208a: Optical upper limit with Kinder observations
  32. GRB 241128A: CrAO ZTSh and Mondy AZT-33IK optical observations
  33. GRB 241209A: EP-FXT follow-up observations
  34. GRB 241209B: SVOM/VT afterglow detection
  35. EP241208a: Global MASTER-Net observations report
  36. EP241208a: EP-FXT follow-up observations
  37. Fermi trigger No 755485387: Global MASTER-Net observations report
  38. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  39. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  40. GRB 241209D: COLIBRÍ detection of the afterglow
  41. GRB 241209A: COLIBRÍ Optical Upper Limit
  42. Fermi GRB 241209D: Global MASTER-Net observations report
  43. GRB 241209A: Fermi GBM Observation
  44. GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
  45. GRB 241209A: GRANDMA/TAROT upper limit
  46. Swift GRB 241209D: Global MASTER-Net observations report
  47. Fermi GRB 241209C: Global MASTER-Net observations report
  48. Fermi GRB 241209E: Global MASTER-Net observations report
  49. GRB 241209B: Swift ToO observations
  50. LIGO/Virgo/KAGRA S241102br: continued GRAWITA observations and detection of an optical transient (AT2024adip)
  51. GRB 241209A: REM optical/NIR observations
  52. GRB 241209A: VLT/X-shooter spectroscopy
  53. GRB 241209A: VLT optical observations
  54. Fermi GRB 241209A: Global MASTER-Net observations report
  55. GRB 241209A: GOTO optical upper limits
  56. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  57. EP241208a: EP detection of a fast X-ray transient
  58. Swift GRB241209.23: Global MASTER-Net observations report
  59. Fermi GRB 241207B: Global MASTER-Net observations report
  60. GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
  61. GRB 241206A: DDOTI Upper Limit on the Afterglow
  62. AT2024adec: X-ray Upper Limits from EP-FXT Observation
  63. EP241206a: BOOTES Global Network optical limits
  64. GRB 241207C: MASTER optical observations
  65. Fermi trigger No 755225799: Global MASTER-Net observations report
  66. GRB 241207C: Tiled Swift observations
  67. Fermi trigger No 755277791: Global MASTER-Net observations report
  68. Fermi GRB 241207A: Global MASTER-Net observations report
  69. EP241206a: Global MASTER-Net observations report
  70. EP241206a: EP detection of a fast X-ray transient
  71. GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
  72. GRB 241206B: SVOM/MXT observations: a probable flare from the QSO 1ES 1959+650
  73. EP241113a: Keck/LRIS spectroscopic observation and tentative redshift
  74. Fermi GRB 241206A: Global MASTER-Net observations report
  75. GRB 241204A: COLIBRÍ Optical Upper Limit
  76. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  77. GRB 241204A: DDOTI Upper Limits on the Afterglow
  78. Fermi GRB 241204A: Global MASTER-Net observations report
  79. GRB 241128A : RAPAS follow-up observations
  80. EP241202b: Upper limits from Fermi-GBM Observations
  81. IceCube-241127A: No transient candidates from the Zwicky Transient Facility
  82. EP241202b: Kinder optical counterpart candidate
  83. Fermi-GBM Sub-Threshold Detection of GRB 241128A
  84. EP241201a: EP-FXT follow-up observations
  85. EP241202b: Global MASTER-Net observations report
  86. EP241202b: EP detection of a fast X-ray transient
  87. EP241201a: NOT optical observations
  88. GRB 241128A: Swift/UVOT Upper Limits
  89. GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
  90. EP241201a: Kinder optical counterpart candidate
  91. LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
  92. EP241201a: Global MASTER-Net observations report
  93. EP241201a: EP detection of a fast X-ray transient
  94. EP241126a: SOAR observations of the optical counterpart
  95. Fermi GRB 241201A: Global MASTER-Net observations report
  96. EP241126a: 1.6m Mephisto Optical Upper Limits
  97. Fermi trigger No 754701230: Global MASTER-Net observations report
  98. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  99. EP241126a: NOT optical observations
  100. GRB 241127A: PRIME near-infrared detection

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