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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"

16161 results found.

  1. GRB 110915A: MITSuME Okayama and Ishigakijima Optical upper limits
  2. GRB 110915A: NOT observations
  3. GRB 110915A: GMG optical upper limit
  4. GRB 110915A: MITSuME Akeno Optical upper limits
  5. GRB 110915A: MASTER-Net early limit
  6. GRB 110905A / X-ray transient MAXI J1836-194: TNT optical observation
  7. GRB 110905A: Potential BAT trigger on MAXI J1836-194
  8. GRB 110903A: Swift/UVOT Upper Limits
  9. GRB 110820A: optical upper limit
  10. GRB 110825A: GMG optical observation
  11. GRB110825A: ROTSE early time optical limit
  12. GRB 110825A: optical afterglow candidate
  13. GRB 110820A: Swift/UVOT Upper Limits
  14. GRB110820A: MITSuME Ishigakijima Optical Upper Limits
  15. GRB 110820A: CrAO optical upper limit
  16. GRB 110820A: MASTER-NET observations
  17. GRB 110818A: Swift/UVOT Upper Limits
  18. GRB 110818A: Optical afterglow and redshift from VLT/X-shooter
  19. GRB 110801A: optical observations at Mt. Terskol observatory
  20. Reprocessed enhanced Swift-XRT positions and GRB products: update
  21. GRB 110808A: VLT/X-shooter spectroscopy
  22. GRB 110808A: Swift detection of a burst with optical counterpart
  23. GRB 110726A: two epochs of SAO RAS optical observations
  24. GRB 110801A: optical observations in CrAO
  25. EVLA observation for Fermi burst GRB 110721A
  26. GRB110731A: MOA optical observations of the steeply fading afterglow
  27. GRB 110801A: SAO RAS optical observations
  28. GRB110801A: MITSuME Ishigakijima Optical Observation at 1 day after the burst
  29. GRB 110801A: MASTER OT observations
  30. GRB110801A: MITSuME Ishigakijima Optical Observation
  31. GRB 110801A: TLS Optical afterglow confirmation
  32. GRB 110801A: Swift detection of a burst with an optical counterpart
  33. GRB 110731A / EVLA upper limits
  34. GRB110731A: MITSuME Ishigakijima Optical Upper Limits
  35. GRB110731A: Swift/UVOT Observations
  36. GRB 110731A: NOT photometry
  37. Fermi-LAT Detection of GRB110731A
  38. GRB 110731A: Swift detection of a burst with an optical counterpart
  39. Sw J1644+57 (GRB 110328A): Continued VLBA Observations
  40. INTEGRAL Weak trigger #6331: GRT Optical Observation
  41. GRB 110726A: optical upper limit in CrAO
  42. GRB 110726A: EVLA observations
  43. GRB 110726A: IAC80 R-band observations
  44. GRB 110726A: ROTSE-III refined analysis, fast decay in early phase
  45. GRB110726A: MITSuME Ishigakijima Optical Observation
  46. GRB 110726A: Liverpool Telescope observations
  47. GRB 110726: ROTSE-III Detection of Optical Counterpart
  48. GRB 110721A: Preliminary Swift/UVOT Upper Limits
  49. GRB 110721A: Gemini-South spectroscopy of the potential optical counterpart
  50. GRB 110721A: potential counterpart candidate
  51. GRB 110709B / EVLA detection of radio counterpart
  52. GRB 110719A: GRT Optical Observation
  53. GRB 110719A: optical limit by "Pi of the Sky"
  54. Swift/UVOT observations of GRB110719A
  55. GRB 110719A: optical upper limit
  56. GRB 110715A optical observations
  57. Swift J1822.3-1606: Transient Magnetar or Be X-ray Binary?
  58. GRB110715A: GROND Detection of the Optical/NIR Afterglow
  59. GRB 110715A: APEX detection of the submm counterpart
  60. GRB110715A: VLT redshift
  61. GRB 110715A: Swift detection of a bright burst with an optical counterpart
  62. GRB 110709B: Additional Gemini observations and deep limits on an optical afterglow
  63. GRB 110709A: Swift/UVOT Upper Limits
  64. GRB 110709B: Swift/UVOT Detection of Possible Optical Flaring
  65. GRB110709A: MITSuME Ishigakijima Optical upper limits
  66. GRB 110709B: Gemini-South optical observations
  67. GRB 110709B: possible quiescent source in DSS
  68. GRB 110709A: MASTER-NET optical observations
  69. GRB 110708A: Liverpool Telescope observations
  70. SGR 1E 1841-045: early optical limit by "Pi of the Sky"
  71. GRB 110625A: Fermi GBM and LAT observations
  72. GRB 110625A: Swift/UVOT Upper Limits
  73. GRB 110625A: GROND detection of a source inside the XRT error circle
  74. GRB 110625A: ROTSE-III Optical Limits
  75. Swift J185003.2-005627: Swift-XRT/UVOT refined analysis
  76. Swift J185003.2-005627: TAROT La Silla observatory optical observations
  77. Swift J185003.2-005627: TAROT Calern observatory optical observations
  78. GRB 110618A: SMARTS optical observations
  79. GRB 110610A: 1.23m CAHA optical observations
  80. GRB 110610A: Swift/UVOT Upper Limits
  81. Swift detection of the X-ray afterglow of GRB 110604A
  82. GRB 110610A: MASTER-NET optical observations
  83. GRB 110530A: optical observations in Mondy observatory
  84. GRB 110530A: optical observations at Mt. Terskol, second epoch
  85. GRB 110530A: Xinglong TNT observation
  86. GRB 110530A: NOT optical observations
  87. GRB110530A: MITSuME Okayama Optical Observation
  88. GRB 110530A: optical observations at Mt. Terskol
  89. GRB 110530A: MASTER OT observations
  90. GRB 110530A: MITSuME Akeno Optical Observation
  91. GRB 110530A: Swift detection of a burst with an optical afterglow
  92. Swift J1644+57/GRB 110328A, Additional HST Observations
  93. GRB 110521A: MASTER prompt optical limit
  94. GRB 110521A: Swift/UVOT Upper Limits
  95. GRB 110520A: NOT optical follow-ups
  96. GRB 110521A - NOT optical observation
  97. GRB 110521A: MASTER synchronous and early optical observations limit
  98. Swift/UVOT observations of GRB110520A
  99. GRB 110520A - NOT optical observation
  100. GRB 110520A: Skynet/DAO optical observations

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