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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"

20392 results found.

  1. GRB 090726: optical transient candidate
  2. Swift XRT and UVOT refned analysis of GRB 090720
  3. GRB 090715B: VLA radio detection
  4. GRB 090720 Source found in ground processing of Swift-BAT data
  5. GRB 090715B: further NOT optical observations
  6. GRB 090709A - CARMA mm Observations
  7. GRB 090715A: VLA observations
  8. GRB 090715B: Swift/UVOT followup observations
  9. GRB 090715B: Enhanced Swift-XRT position
  10. GRB 090715B: Observation of the optical afterglow
  11. GRB 090715B: NOT optical observations
  12. GRB 090715B: Swift detection of a burst with a possible optical counterpart
  13. Detection of GRB 090618 by RT-2 Experiment onboard the CORONAS-PHOTON Satellite
  14. VLA radio observations of GRB 090709A
  15. GRB 090621B: MTM-500 optical observations
  16. GRB 090709A: deep optical observation with the 10.4m GTC
  17. GRB 090709A: Swift UVOT upper limits
  18. GRB 090709A: WHT LIRIS observations
  19. GRB 090709A: P60 Observations
  20. GRB 090709A: NOT optical observations
  21. GRB 090709A: RAPTOR Limits During Gamma-Ray Emission
  22. GRB090709A: High Energy BAT/XRT Analysis Suggests Low to Moderate Redshift
  23. GRB 090709A: Wyoming Infrared Observatory NIR upper limits
  24. GRB 090709A, RIMOTS optical upper limits
  25. GRB 090709A: Enhanced Swift-XRT position
  26. GRB 090709A: Subaru NIR observation
  27. GRB 090709 : planned Suzaku-ToO observation
  28. GRB 090709: Faulkes Telescope North Upper Limits
  29. GRB 090709: PAIRITEL NIR Upper Limits
  30. GRB 090709: Swift detection of a bright burst
  31. GRB 090708: Early RAPTOR Optical Limits
  32. GRB 090708, Swift-BAT refined analysis
  33. GRB 090706: Fermi GBM detection
  34. GRB 090705: PAIRITEL NIR Observations
  35. GRB 090705: Swift detection of a possible burst
  36. XRF 090702 : RTT150 optical observations
  37. GRB 090529: CrAO optical upper limit
  38. GRB 090529: MTM-500 optical observations
  39. GRB 090702: UVOT upper limits
  40. XRF 090702: VLT imaging
  41. XRF 090702: Swift-XRT afterglow position
  42. GRB 090404: Deep optical imaging and possible host association
  43. GRB 090628: Swift XRT refined analysis
  44. GRB 090628: Swift/UVOT Upper Limits
  45. GRB080628: SAO RAS optical observations
  46. GRB 090628: GROND upper limits
  47. GRB 090628: Enhanced Swift-XRT position
  48. GRB 090626: IPN localization
  49. GRB 090423: Spitzer observations of the z~8.3 burst
  50. GRB 090625B: Swift/UVOT Upper Limits
  51. GRB 090625B: GROND upper limits
  52. GRB090618: HCT optical observations
  53. GRB 090618: SARA Second Epoch Observations
  54. GRB 090625B: Swift observation of the INTEGRAL GRB 090625B
  55. GRB 090618: Correction to GCN 9568
  56. GRB 090618: Suzaku WAM observation of the prompt emission
  57. GRB 090621A: Enhanced Swift-XRT position
  58. GRB 090621B: GRT Optical Observation
  59. GRB 090621A: GRT Optical Observation
  60. GRB 090621B: I-band observations from 1.23m CAHA
  61. GRB 090621B: P60 Observations
  62. GRB 090621: Fermi GBM observation
  63. GRB 090621B: VLA observations
  64. Konus-Wind and Konus-RF observations of GRB 090618
  65. GRB 090621B: Swift/UVOT Upper Limits
  66. GRB 090621B: Swift-XRT refined analysis
  67. GRB 090621B: RTT150 optical observations
  68. GRB 090621B: Swift detection of a short hard burst
  69. GRB 090621: Swift/UVOT Upper Limits
  70. GRB090618: Spectrum and photometry from 6.0m BTA
  71. GRB 090621: Swift detection of a burst
  72. GRB090618: OAA-OAUV Optical observations
  73. GRB 090618: Fermi GBM observation
  74. VLA radio detection of GRB 090618
  75. GRB 090618 15GHz radio detection
  76. GRB090618 - Continued optical monitoring and light curve break
  77. GRB 090618: Swift-BAT refined analysis
  78. GRB 090618: SARA observations
  79. GRB090618: Swift/UVOT bright afterglow detection
  80. GRB 090618: SDSS host detection
  81. Swift XRT observations of GRB 090531A
  82. GRB 090618: AGILE observations
  83. GRB 090618: Enhanced Swift-XRT position
  84. GRB 090618 Faulkes Telescope North observations
  85. GRB090618: P60 Optical Afterglow
  86. GRB 090618: Swift detection of a bright burst with optical afterglow
  87. SGR 0418+5729 Fermi/GBM Detection of Pulsations
  88. GRB 090424: WSRT Radio Observations
  89. RXTE Discovery of Pulsations from SGR 0418+5729
  90. Discovery of a new soft gamma repeater source, SGR 0418+5729
  91. GRB 090607: Swift/UVOT Upper Limits
  92. GRB 090607: GRAS001 optical observations
  93. GRB 090607: Faulkes Telescope North observations
  94. GRB 090607: Swift detection of a burst
  95. GRB 090530: Further NOT optical observations
  96. GRB 090530: RTT150 Optical Observation
  97. GRB 090529A: RTT150 Optical Observations
  98. GMRT observation of GRB 090424 afterglow
  99. GRB090529: Further NOT optical observations
  100. GRB 090531B: GROND observation

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