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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"

20546 results found.

  1. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  2. GRB031220: Palomar Observations
  3. GRB 031203 I-band monitoring
  4. GRB 2974 follow-up observations
  5. GRB031203, improved XMM position
  6. GRB 031203: Discovery of a dust echo
  7. GRB 031203: SMARTS optical monitoring
  8. GRB 021203: A Normal GRB viewed far off axis?
  9. XMM-Newton Observations of GRB031203: Preliminary Images
  10. GRB 031203: Variable Radio Source
  11. GRB 031203: Magellan spectrum of possible GRB host
  12. GRB 031203: Optical/IR Astrometry
  13. GRB031203 K prime photometry: correction to galaxy coordinates
  14. GRB 031203: Deep NIR NTT & VLT observations
  15. GRB031203: K' Photometry of the likely GRB host
  16. GRB 031203: Radio detection
  17. GRB 031203: Further reports on December 4 observations
  18. GRB 031203: IR NTTobservations do not confirm REM detection
  19. GRB 031203: z ~ 10 or Fragmented Dust in the Circumburst Environment?
  20. GRB 031203: Apparent Spectral Break
  21. GRB 031203: IR REM Observations
  22. GRB031203: Optical Observations
  23. GRB 031203: Optical/IR SMARTS Observations
  24. GRB031111A, prompt optical observations
  25. GRB 031111, Radio observations
  26. GRB 031111: Optical observations
  27. GRB 031111, optical observations
  28. SN 2003jd (SN/GRB?) -- X-ray Observations
  29. GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
  30. Lulin optical follow-up observations of GRB031026
  31. SN 2003jd (SN/GRB?), Radio Observations
  32. GRB 031026: Further Ic Observations
  33. GRB 031026 (=H2882): Evidence for High Redshift from Prompt
  34. Peculiar Type Ic SN 2003jd (SN/GRB?), optical spectrum
  35. GRB 031026: Ic Observations
  36. GRB030329: radio observations at RT-22 (CrAO)
  37. XRF 030824: additional observations at CFHT
  38. SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters
  39. XRF 030723: Subaru Optical Observations
  40. XRF 030824: observations at CFHT
  41. XRF 030723: Detection of the likely host galaxy
  42. GRB030913: Subaru Optical Observations
  43. GRB 030913: ROTSE-3c Optical Observations
  44. GRB030913, candidate afterglow observations
  45. GRB 030913, optical candidate
  46. GRB030913: AAVSO optical observations
  47. GRB 030913, BOOTES observations
  48. GRB030913 (=H2849): Confirmation of the Flight Localization
  49. GRB030913 (=H2849): TAROT Observations
  50. Magellan Observations of GRB030725 (=H2779)
  51. XRF 020427: Gemini-South Spectroscopic Observations of the Host
  52. XRF030824: Optical observations
  53. IBAS detection of bursts from SGR 1806-20
  54. Radio Observations of SGR1806-20
  55. INTEGRAL ToO OBSERVATIONS OF SGR1806-20: CALL FOR CORRELATED OBSERVATIONS
  56. XRF030824: Second-epoch Palomar observations
  57. XRF030824: optical observations
  58. GRB030823: optical observations
  59. GRB030823: Palomar observations
  60. XRF030824: Palomar observations
  61. RAPTOR observations of GRB030823
  62. Lulin follow-up observations of GRB030823
  63. GRB 030817 = H2808 TAROT optical observations
  64. SGR 1808-20 (=H2802): A Possible new SGR
  65. GRB 021206 Optical Observations
  66. XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed
  67. XRF 030723: Detection of a rebrightening in the optical afterglow
  68. GRB030725: Optical observations
  69. GRB021206 optical counterpart upper limit
  70. XRF030723: Re-analysis of ROTSE-III early images
  71. XRF030723 (=H2777): Second Epoch Magellan Observations
  72. GRB 030725: optical observations.
  73. GRB030725, optical transient observations
  74. XRF030723 Radio Observations
  75. XRF 030723: confirmation of fading optical counterpart
  76. XRF030723(=H2777): Chandra Observations
  77. XRF 030723: VLT spectra
  78. Magellan Observations of XRF030723 (=H2777)
  79. GRB030723: Upper limits from historical observations
  80. GRB030725, possible optical transient
  81. XRF030723: Palomar observations and proposed counterpart
  82. XRF030723: optical observations
  83. XRF030723 (= H2777): Chandra Observations Scheduled
  84. XRF030723, ROTSE-III Early Observations
  85. XRF030723, BVRcIc field photometry
  86. XRF 030723, optical observations
  87. XRF030723, optical observations
  88. XRF 030723, optical observations
  89. GRB030723, optical observations
  90. Konus-Wind detection of the bursts from SGR1806-20 region
  91. SGR 1806-20, submm observations
  92. RXTE PCA Observations of SGR1806-20 Region
  93. GRB030329: RTT150 optical observations
  94. GRB030329, optical observation in May
  95. GRB030418: R optical observations
  96. GRB 021206, Radio afterglow candidate
  97. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  98. GRB030329, SPM optical observations (Correction of GCN2075 R band)
  99. GRB 030528: Infrared Observations and the Proposed IR Counterpart
  100. GRB 030528: Optical Observations

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