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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"

21954 results found.

  1. EP241213a/GRB241213a: Likely joint detection and INTEGRAL/SPI-ACS counterpart
  2. GRB 241213A: REM optical/NIR upper limits
  3. GRB241212A: OHP/T193 optical observations
  4. GRB 241213A: SAO RAS optical upper limit
  5. Swift GRB 241213A: Global MASTER-Net observations report
  6. GRB 241212A : SVOM/VT bright optical afterglow
  7. GRB 241209B: GRANDMA/TRT upper limit
  8. GRB 241207A: TSHAO Zeiss-1000 optical observations
  9. GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations
  10. GRB 241209A: Chandra X-ray Detection
  11. GRB 241209A: Redshift of the likely host galaxy z = 0.784 from OSIRIS+/GTC
  12. GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
  13. GRB 241209D: REM optical/NIR upper limits
  14. GRB 241209B: Swift-XRT afterglow detection
  15. EP241208a: Optical upper limit with Kinder observations
  16. GRB 241128A: CrAO ZTSh and Mondy AZT-33IK optical observations
  17. GRB 241209A: EP-FXT follow-up observations
  18. GRB 241209B: SVOM/VT afterglow detection
  19. EP241208a: Global MASTER-Net observations report
  20. EP241208a: EP-FXT follow-up observations
  21. Fermi trigger No 755485387: Global MASTER-Net observations report
  22. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  23. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  24. GRB 241209D: COLIBRÍ detection of the afterglow
  25. GRB 241209A: COLIBRÍ Optical Upper Limit
  26. Fermi GRB 241209D: Global MASTER-Net observations report
  27. GRB 241209A: Fermi GBM Observation
  28. GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
  29. GRB 241209A: GRANDMA/TAROT upper limit
  30. Swift GRB 241209D: Global MASTER-Net observations report
  31. Fermi GRB 241209C: Global MASTER-Net observations report
  32. Fermi GRB 241209E: Global MASTER-Net observations report
  33. GRB 241209B: Swift ToO observations
  34. LIGO/Virgo/KAGRA S241102br: continued GRAWITA observations and detection of an optical transient (AT2024adip)
  35. GRB 241209A: REM optical/NIR observations
  36. GRB 241209A: VLT/X-shooter spectroscopy
  37. GRB 241209A: VLT optical observations
  38. Fermi GRB 241209A: Global MASTER-Net observations report
  39. GRB 241209A: GOTO optical upper limits
  40. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  41. EP241208a: EP detection of a fast X-ray transient
  42. Swift GRB241209.23: Global MASTER-Net observations report
  43. Fermi GRB 241207B: Global MASTER-Net observations report
  44. GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
  45. GRB 241206A: DDOTI Upper Limit on the Afterglow
  46. AT2024adec: X-ray Upper Limits from EP-FXT Observation
  47. EP241206a: BOOTES Global Network optical limits
  48. GRB 241207C: MASTER optical observations
  49. Fermi trigger No 755225799: Global MASTER-Net observations report
  50. GRB 241207C: Tiled Swift observations
  51. Fermi trigger No 755277791: Global MASTER-Net observations report
  52. Fermi GRB 241207A: Global MASTER-Net observations report
  53. EP241206a: Global MASTER-Net observations report
  54. EP241206a: EP detection of a fast X-ray transient
  55. GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
  56. GRB 241206B: SVOM/MXT observations: a probable flare from the QSO 1ES 1959+650
  57. EP241113a: Keck/LRIS spectroscopic observation and tentative redshift
  58. Fermi GRB 241206A: Global MASTER-Net observations report
  59. GRB 241204A: COLIBRÍ Optical Upper Limit
  60. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  61. GRB 241204A: DDOTI Upper Limits on the Afterglow
  62. Fermi GRB 241204A: Global MASTER-Net observations report
  63. GRB 241128A : RAPAS follow-up observations
  64. EP241202b: Upper limits from Fermi-GBM Observations
  65. IceCube-241127A: No transient candidates from the Zwicky Transient Facility
  66. EP241202b: Kinder optical counterpart candidate
  67. Fermi-GBM Sub-Threshold Detection of GRB 241128A
  68. EP241201a: EP-FXT follow-up observations
  69. EP241202b: Global MASTER-Net observations report
  70. EP241202b: EP detection of a fast X-ray transient
  71. EP241201a: NOT optical observations
  72. GRB 241128A: Swift/UVOT Upper Limits
  73. GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
  74. EP241201a: Kinder optical counterpart candidate
  75. LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
  76. EP241201a: Global MASTER-Net observations report
  77. EP241201a: EP detection of a fast X-ray transient
  78. EP241126a: SOAR observations of the optical counterpart
  79. Fermi GRB 241201A: Global MASTER-Net observations report
  80. EP241126a: 1.6m Mephisto Optical Upper Limits
  81. Fermi trigger No 754701230: Global MASTER-Net observations report
  82. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  83. EP241126a: NOT optical observations
  84. GRB 241127A: PRIME near-infrared detection
  85. GRB 241128A: Mondy optical observations
  86. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  87. Swift-XRT observations of IceCube -241127A
  88. Swift GRB 241128A: Global MASTER-Net observations report
  89. Fermi-LAT gamma-ray observations of IceCube-241127A
  90. EP241126a: SVOM/VT observations
  91. GRB 241128A: NOT optical observations
  92. GRB 241128A: LCO optical detection
  93. GRB 241128A: 1.5m OSN optical afterglow detection
  94. LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
  95. Fermi trigger No 754492985: Global MASTER-Net observations report
  96. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  97. GRB 241127A: Swift/UVOT Detection
  98. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  99. EP241126a: WFST Observations
  100. LIGO/Virgo/KAGRA S241125n: Update on Coincidence False Alarm Method

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