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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"

28295 results found.

  1. LIGO/Virgo/KAGRA S240910ci: NED Galaxies in the Localization Volume
  2. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  3. LIGO/Virgo/KAGRA S240910ci: Updated Sky localization and EM Bright Classification
  4. LIGO/Virgo/KAGRA S240910ci: Identification of a GW compact binary merger candidate
  5. GRB 240910A: SVOM/GRM observation
  6. EP240908a: Mondy and AbAO follow-up observations
  7. EP240908a: Updates on the WXT detection result around the trigger time
  8. LIGO/Virgo/KAGRA S240908bs: Upper limits from Swift/BAT-GUANO
  9. LIGO/Virgo/KAGRA S240907cg: Upper limits from Swift/BAT-GUANO
  10. GRB 240905B: Fermi GBM Observation
  11. Fermi trigger No 747553301: Global MASTER-Net observations report
  12. EP240908a: TRT optical upper limit
  13. EP240908a: EP detection of a fast X-ray transient
  14. LIGO/Virgo/KAGRA S240908dg: Updated Sky localization
  15. LIGO/Virgo/KAGRA S240908bs: Updated Sky localization
  16. LIGO/Virgo/KAGRA S240908dg: Identification of a GW compact binary merger candidate
  17. LIGO/Virgo/KAGRA S240908bs: Identification of a GW compact binary merger candidate
  18. LIGO/Virgo/KAGRA S240907cg: Updated Sky localization
  19. LIGO/Virgo/KAGRA S240907cg: Identification of a GW compact binary merger candidate
  20. GRB 240905E: GIT optical upper limit
  21. GRB 240905B: Swift-XRT observations
  22. GRB 240905E: Gaoyazi/GOT optical upper limits
  23. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  24. GRB 240905E: J-band observations with WINTER
  25. GRB 240905E: CrAO Optical Afterglow observations, possible OT candidate
  26. GRB 240905E: AKO Optical Upper Limit
  27. GRB 240905E: SVOM/C-GFT optical upper limit
  28. GRB 240905E: OHP/MISTRAL T193 optical upper limit
  29. GRB 240905E: NOT optical upper limits
  30. GRB 240905E: REM optical/NIR upper limits
  31. GRB 240902B: AstroSat CZTI detection of a long burst
  32. GRB 240905E: Swift-XRT refined Analysis
  33. GRB 240902A: AstroSat CZTI detection of a long burst
  34. GRB 240905E: LCOGT Optical Upper Limit
  35. GRB 240905E: Swift/UVOT Upper Limits
  36. GRB 240905E: SAO RAS optical upper limit
  37. GRB 240905E: Nanshan/HMT optical upper limit
  38. GRB 240905E: Swift detection of a burst
  39. GRB 240905B: AstroSat CZTI detection and localization
  40. LIGO/Virgo/KAGRA S240825ar: Upper limits from Swift/BAT-GUANO
  41. LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO
  42. LIGO/Virgo/KAGRA S240902bq: Updated Sky localization
  43. GRB 240828A: GECAM detection
  44. LIGO/Virgo/KAGRA S240902bq: Identification of a GW compact binary merger candidate
  45. GRB 240825A: MeerLICHT afterglow detection
  46. GRB 240828A: SAO RAS AS-500(2) optical observations
  47. GRB 240821A: VLT spectroscopic observations
  48. GRB 240825A: TSHAO Optical Upper Limit
  49. GRB240828B: REM optical/NIR upper limits
  50. GRB 240828B: AbAO optical upper limit
  51. GRB 240825A: SOAR observations
  52. GRB 240828B: Mephisto optical upper limit
  53. GRB 240828B: GRANDMA Optical Upper Limit
  54. LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
  55. LIGO/Virgo/KAGRA S240830gn: Updated Sky localization and EM Bright Classification
  56. GRB 240829A: Swift-BAT refined analysis
  57. GRB 240825A: Swift-BAT refined analysis
  58. LIGO/Virgo/KAGRA S240830gn: Identification of a GW compact binary merger candidate
  59. GRB 240828B: J-band upper limit from WINTER
  60. GRB 240828B: GMG Optical Upper Limit
  61. GRB 240828B: SVOM/C-GFT optical upper limit
  62. GRB 240828B: SAO RAS optical upper limit
  63. GRB 240828A: SAO RAS optical observations
  64. Fermi trigger No 746587425: Global MASTER-Net observations report
  65. GRB 240828A: Fermi GBM Observation
  66. GRB 240828A: KAIT Optical Afterglow Candidate
  67. GRB 240825A: SVOM/VT optical detection
  68. GRB 240828A: Swift-XRT afterglow detection
  69. GRB 240825A: further SAO RAS optical observations
  70. GRB 240825A: iTelescope optical observations
  71. GRB 240828B: Swift-XRT afterglow detection
  72. GRB 240829A: Swift detection of a burst
  73. Fermi GRB 240828A: Bassano Bresciano Observatory upper limit
  74. GRB 240825A: Upper limits from a neutrino search with IceCube
  75. GRB 240821A: PRIME near-infrared observations
  76. GRB 240828B : Detection of a possible very soft X-ray transient by SVOM/ECLAIRs
  77. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  78. GRB 240825A: SAO RAS optical observations
  79. GRB 240824A: GIT optical upper limit
  80. LIGO/Virgo/KAGRA S240825ar: Updated Sky localization
  81. LIGO/Virgo/KAGRA S240825ar: Updated Sky localization
  82. GRB 240825A: NUTTelA-TAO / BSTI Optical Limits
  83. GRB 240825A: GMG Continued Optical Observation on the Second Night
  84. GRB 240825A: PRIME near-infrared detection
  85. GRB 240825A: Fermi GBM Observation
  86. GRB 240825A : MISTRAL/T193 OHP optical follow-up of the afterglow
  87. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  88. GRB 240825A: Swift/UVOT Detection
  89. GRB 240825A: REM detection of the optical/NIR afterglow
  90. GRB 240825A: Swift-XRT refined Analysis
  91. GRB 240825A: VLT/X-shooter redshift
  92. GRB 240825A: Montarrenti Observatory optical observations
  93. GRB 240825A: Enhanced Swift-XRT position
  94. GRB 240825A: LCO optical observations
  95. GRB 240824B: KAIT optical upper limit
  96. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  97. GRB 240824B: Fermi GBM Observation
  98. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  99. GRB 240824B: NOT optical upper limit
  100. GRB 240825A: GMG Optical Observation

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