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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"

20967 results found.

  1. GRB 031203: IR NTTobservations do not confirm REM detection
  2. GRB 031203: Apparent Spectral Break
  3. GRB 031203: IR REM Observations
  4. GRB031203: Optical Observations
  5. GRB 031203: Optical/IR SMARTS Observations
  6. GRB031111A, prompt optical observations
  7. GRB 031111, Radio observations
  8. GRB 031111: Optical observations
  9. GRB 031111, optical observations
  10. SN 2003jd (SN/GRB?) -- X-ray Observations
  11. XRF031109 (=H2919): A very long XRF localized by HETE
  12. GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
  13. Lulin optical follow-up observations of GRB031026
  14. SN 2003jd (SN/GRB?), Radio Observations
  15. GRB 031026: Further Ic Observations
  16. GRB 031026 (=H2882): Evidence for High Redshift from Prompt
  17. Peculiar Type Ic SN 2003jd (SN/GRB?), optical spectrum
  18. GRB 031026: Ic Observations
  19. GRB030329: radio observations at RT-22 (CrAO)
  20. XRF 030824: additional observations at CFHT
  21. SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters
  22. IPN detection of continued activity from SGR1806-20
  23. XRF 030723: Subaru Optical Observations
  24. XRF 030824: observations at CFHT
  25. GRB030913: Subaru Optical Observations
  26. GRB 030913: ROTSE-3c Optical Observations
  27. GRB030913, candidate afterglow observations
  28. GRB 030913, optical candidate
  29. GRB030913: AAVSO optical observations
  30. GRB 030913, BOOTES observations
  31. GRB030913 (=H2849): Confirmation of the Flight Localization
  32. GRB030913 (=H2849): TAROT Observations
  33. Magellan Observations of GRB030725 (=H2779)
  34. XRF 020427: Gemini-South Spectroscopic Observations of the Host
  35. XRF030824: Optical observations
  36. IBAS detection of bursts from SGR 1806-20
  37. Radio Observations of SGR1806-20
  38. INTEGRAL ToO OBSERVATIONS OF SGR1806-20: CALL FOR CORRELATED OBSERVATIONS
  39. XRF030824: Second-epoch Palomar observations
  40. XRF030824: optical observations
  41. GRB030823: optical observations
  42. GRB030823: Palomar observations
  43. XRF030824: Palomar observations
  44. RAPTOR observations of GRB030823
  45. Lulin follow-up observations of GRB030823
  46. IPN detection of continued activity from SGR1806-20
  47. GRB 030817 = H2808 TAROT optical observations
  48. SGR 1808-20 (=H2802): A Possible new SGR
  49. GRB 021206 Optical Observations
  50. XRF 030723: Detection of a rebrightening in the optical afterglow
  51. GRB030725: Optical observations
  52. GRB021206 optical counterpart upper limit
  53. XRF030723: Re-analysis of ROTSE-III early images
  54. XRF030723 (=H2777): Second Epoch Magellan Observations
  55. GRB 030725: optical observations.
  56. GRB030725, optical transient observations
  57. XRF030723 Radio Observations
  58. XRF 030723: confirmation of fading optical counterpart
  59. XRF030723(=H2777): Chandra Observations
  60. XRF 030723: VLT spectra
  61. Magellan Observations of XRF030723 (=H2777)
  62. GRB030723: Upper limits from historical observations
  63. GRB030725, possible optical transient
  64. XRF030723: Palomar observations and proposed counterpart
  65. XRF030723: optical observations
  66. XRF030723 (= H2777): Chandra Observations Scheduled
  67. XRF030723, ROTSE-III Early Observations
  68. XRF030723, BVRcIc field photometry
  69. XRF 030723, optical observations
  70. XRF030723, optical observations
  71. XRF 030723, optical observations
  72. GRB030723, optical observations
  73. Konus-Wind detection of the bursts from SGR1806-20 region
  74. SGR 1806-20, submm observations
  75. RXTE PCA Observations of SGR1806-20 Region
  76. GRB030329: RTT150 optical observations
  77. GRB030329, optical observation in May
  78. GRB030418: R optical observations
  79. GRB 021206, Radio afterglow candidate
  80. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  81. GRB030329, SPM optical observations (Correction of GCN2075 R band)
  82. GRB 030528: Infrared Observations and the Proposed IR Counterpart
  83. GRB 030528: Optical Observations
  84. GRB 030528, radio observations
  85. GRB030528(=H2724): Observations with the Chandra X-ray Observatory
  86. GRB030329, further radio observations at GMRT
  87. GRB030329, SPM optical observations
  88. GRB030528: Chandra TOO Planned
  89. GRB 030519B: optical observations.
  90. MASTER: optical observation GRB030601
  91. GRB 030329: optical observations
  92. GRB 030329/SN 2003dh: Jitter Episode
  93. GRB 030329: Optical Observations
  94. GRB 030528: Optical observations at RIKEN
  95. GRB 030416: Optical Observations
  96. GRB030329, Optical observations
  97. GRB 030329/SN 2003dh: Possible increase in brightness
  98. GRB 030329: HST ACS Observations of the Host
  99. GRB 030329 Optical Observations
  100. GRB030329: XMM-Newton observation

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