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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"

5060 results found.

  1. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  2. Fermi GRB 241207B: Global MASTER-Net observations report
  3. Fermi GRB 241207A: Global MASTER-Net observations report
  4. GRB 241206C: SVOM/GRM observation of a likely short burst
  5. GRB 241204A: DDOTI Upper Limits on the Afterglow
  6. GRB 241204A: Fermi GBM Observation
  7. Fermi GRB 241204A: Global MASTER-Net observations report
  8. GRB 241204A: Fermi-LAT detection
  9. EP241202b: Kinder optical counterpart candidate
  10. EP241202b: Global MASTER-Net observations report
  11. EP241201a: Kinder optical counterpart candidate
  12. LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
  13. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  14. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  15. EP241126a: GSP detects optical counterpart
  16. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  17. Konus-Wind detection of GRB 241117A
  18. IPN triangulation of GRB 241117A
  19. GRB 241114B: Insight-HXMT/HE detection
  20. Fermi GRB 241118A: Global MASTER-Net observations report
  21. GRB 241117A: Fermi GBM Detection
  22. Fermi GRB 241117A: Global MASTER-Net observations report
  23. GRB 241117A: Fermi GBM Final Real-time Localization
  24. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  25. EP241113a: Swift XRT weak detection
  26. GRB 241113A: J-band observations with WINTER
  27. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  28. GRB 241113A: KAIT optical observations
  29. EP241113b: Global MASTER-Net observations report
  30. GRB 241113A: REM detection of the optical/NIR afterglow
  31. Fermi trigger No 753166198: Global MASTER-Net observations report
  32. GRB 241112B: AbAO optical upper limit
  33. IPN triangulation of GRB 241107A (short/hard)
  34. Fermi trigger No 752878030: Global MASTER-Net observations report
  35. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  36. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  37. EP241107a: AKO Optical Afterglow Follow-Up Observations
  38. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  39. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  40. EP241107a: AKO Optical Afterglow Detection
  41. EP241101a: CrAO ZTSH optical observations
  42. GRB 241030A: Mondy optical observations
  43. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  44. GRB 240511A: LCO upper limits
  45. Fermi GRB 241105A: Global MASTER-Net observations report
  46. EP241103a: GIT optical upper limit
  47. EP241021a: OHP/T193 further optical observations
  48. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  49. EP241103a: GOTO optical upper limit
  50. EP241103a: Swift XRT detection and improved X-ray position
  51. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  52. EP241103a: GSP optical upper limit
  53. EP241103A: LCO optical observations
  54. EP241103a: Global MASTER-Net observations report
  55. GRB 241030A: Rapid release of TESS data.
  56. GRB241030A: OHP/T193 optical observations
  57. Fermi trigger No 752083996: Global MASTER-Net observations report
  58. EP EP241030a: Global MASTER-Net observations report
  59. Fermi trigger No 752006065: Global MASTER-Net observations report
  60. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  61. GRB 241030B: AKO Optical Afterglow Detection
  62. GRB 241030B: Prompt enhanced Swift-XRT position
  63. GRB 241030A: Fermi-LAT detection
  64. GRB 241026A: LBT optical observations
  65. GRB 241030A: SVOM/VT optical afterglow observations
  66. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  67. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  68. GRB 241030A: Fermi GBM Final Real-time Localization
  69. EP241021a: SAO RAS observations of rebrightening
  70. GRB 241029A: GOTO optical afterglow detection
  71. EP 241026b: LBT possible optical counterpart (brightening source)
  72. EP EP241026b: Global MASTER-Net observations report
  73. Fermi GRB 241026A: Global MASTER-Net observations report
  74. GRB 241025A: COLIBRÍ Detection of the Afterglow
  75. Fermi GRB 241025A: Global MASTER-Net observations report
  76. GRB 241025A : SVOM/VT optical afterglow observations
  77. Fermi trigger No 750788395: Global MASTER-Net observations report
  78. Fermi GRB 241016A: Global MASTER-Net observations report
  79. IceCube Alert 241016.04: Global MASTER-Net observations report
  80. GRB 241009A: LCO optical upper limits
  81. GRB 241006A: ATCA Radio Upper Limits
  82. Fermi trigger No 750211959: Global MASTER-Net observations report
  83. GRB 240821A: Host galaxy redshift from VLT/X-shooter
  84. IceCube Alert 241006.94: Global MASTER-Net observations report
  85. Fermi trigger No 749721670: Global MASTER-Net observations report
  86. Fermi trigger No 749630753: Global MASTER-Net observations report
  87. GRB 241001A : SVOM/VT optical detection
  88. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  89. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  90. GRB 241002B: GOTO optical counterpart candidate
  91. GRB 241002A: 1.5m OSN optical upper limit
  92. LIGO/Virgo/KAGRA S241002e: Identification of a GW compact binary merger candidate
  93. EP EP240930a: Global MASTER-Net observations report
  94. LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate
  95. Fermi GRB 240929A: Global MASTER-Net observations report
  96. LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
  97. LIGO/Virgo S240919bn: GOTO optical upper limits
  98. EP240919a / GRB 240919A: KAIT optical upper limit
  99. EP240919a: GOTO optical upper limits
  100. EP EP240918a: Global MASTER-Net observations report

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