Optical Detection of the Pictor a Jet and Tidal Tail: Evidence Against an Ic/CMB Jet

Gentry, Eric S.; Marshall, Herman L.; Hardcastle, M. J.; Perlman, Eric S.; Birkinshaw, Mark; Worrall, D. M.; Lenc, E.; Siemiginowska, Aneta; Urry, C. Megan

doi:10.1088/0004-637x/808/1/92

Cited by 10 publications

(17 citation statements)

References 24 publications

(42 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, strong jet-medium interaction on larger scales cannot be ruled out from our observations. Indeed, jet stratification possibly arising due to strong jet-medium interaction has been suggested for the X-ray jet of Pictor A by Hardcastle et al (2015).…”

Section: Discussionmentioning

confidence: 99%

“…Inskip et al (2010), using near-IR data, concluded that Pictor A's surface brightness distribution is best modelled by a disky galaxy profile with a nuclear point source. A tidal tail was recently discovered by Gentry et al (2015), starting 18 ′′ (12 kpc) north of Pictor A, sweeping to the west along a path about 60 kpc long. This long tail indicates the occurrence of a merger event some hundred million years ago.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Integral field spectroscopy of the circum-nuclear region of the radio Galaxy Pictor A

Couto

Storchi‐Bergmann

Robinson

et al. 2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

We present optical integral field spectroscopy of the inner 2.5 × 3.4 kpc 2 of the broadline radio galaxy Pictor A, at a spatial resolution of ≈ 400 pc. Line emission is observed over the whole field-of-view, being strongest at the nucleus and in an elongated linear feature (ELF) crossing the nucleus from the south-west to the north-east along PA ≈ 70 • . Although the broad double-peaked Hα line and the [O i]6300/Hα and [S ii]6717+31/Hα ratios are typical of AGNs, the [N ii]6584/Hα ratio (0.15 − 0.25) is unusually low. We suggest that this is due to the unusually low metallicity of the gas. Centroid velocity maps show mostly blueshifts to the south and redshifts to the north of the nucleus, but the velocity field is not well fitted by a rotation model. Velocity dispersions are low (< 100 km s −1 ) along the ELF, ruling out a jet-cloud interaction as the origin of this structure. The ELF shows both blueshifts and redshifts in channel maps, suggesting that it is close to the plane of the sky. The ELF is evidently photoionized by the AGN, but its kinematics and inferred low metallicity suggest that this structure may have originated in a past merger event with another galaxy. We suggest that the gas acquired in this interaction may be feeding the ELF.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Integral field spectroscopy of the circum-nuclear region of the radio Galaxy Pictor A

Couto

Storchi‐Bergmann

Robinson

et al. 2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

show abstract

“…While some other jets are comparably long, no other known jet boasts the same combination of length, number of visible components and low redshift that 3C 111 does. For example, the jet of Pic A (Marshall et al 2010;Gentry et al 2015;Hardcastle et al 2016), which is similarly straight, longer in angular extent (almost 4'), and is about 30% nearer, has only three components that have been detected in the near-IR, while the jet of 3C 273 (Jester et al 2006), which extends for a somewhat greater distance from its host galaxy and is somewhat brighter, is nearly 4× as far at a redshift z = 0.158. The analysis discussed in this paper strongly disfavors the EC/CMB model as the dominant X-ray emission mechanism in several of the components of 3C 111's jet.…”

Section: Discussionmentioning

confidence: 99%

The Spectacular Radio-Near-Ir-X-Ray Jet of 3c 111: The X-Ray Emission Mechanism and Jet Kinematics

Clautice

Perlman

Georganopoulos

et al. 2016

ApJ

Self Cite

View full text Add to dashboard Cite

Relativistic jets are the most energetic manifestation of the active galactic nucleus (AGN) phenomenon. AGN jets are observed from the radio through gamma-rays and carry copious amounts of matter and energy from the sub-parsec central regions out to the kiloparsec and often megaparsec scale galaxy and cluster environs. While most spatially resolved jets are seen in the radio, an increasing number have been discovered to emit in the optical/near-IR and/or X-ray bands. Here we discuss a spectacular example of this class, the 3C 111 jet, housed in one of the nearest, double-lobed FR II radio galaxies known. We discuss new, deep Chandra and HST observations that reveal both near-IR and X-ray emission from several components of the 3C 111 jet, as well as both the northern and southern hotspots. Important differences are seen between the morphologies in the radio, X-ray, and near-IR bands. The long (over 100 kpc on each side), straight nature of this jet makes it an excellent prototype for future, deep observations, as it is one of the longest such features seen in the radio, near-IR/optical and X-ray bands. Several independent lines of evidence, including the X-ray and broadband spectral shape as well as the implied velocity of the approaching hotspot, lead us to strongly disfavor the EC/CMB model and instead favor a two-component synchrotron model to explain the observed X-ray emission for several jet components. Future observations with NuSTAR, HST, and Chandra will allow us to further constrain the emission mechanisms.

show abstract

“…Hubble Space Telescope (HST) observations of the jet were taken as part of this project, but are not described here: see Gentry et al (2015) for details of the observations and their results. We comment on the implications of these observations for models of the jet in the discussion.…”

Section: Other Datamentioning

confidence: 99%

DeepChandraobservations of Pictor A

Hardcastle

Lenc

Birkinshaw

et al. 2015

Mon. Not. R. Astron. Soc.

116

View full text Add to dashboard Cite

We report on deep Chandra observations of the nearby broad-line radio galaxy Pictor A, which we combine with new Australia Telescope Compact Array (ATCA) observations. The new X-ray data have a factor 4 more exposure than observations previously presented and span a 15-year time baseline, allowing a detailed study of the spatial, temporal and spectral properties of the AGN, jet, hotspot and lobes. We present evidence for further time variation of the jet, though the flare that we reported in previous work remains the most significantly detected time-varying feature. We also confirm previous tentative evidence for a faint counterjet. Based on the radio through X-ray spectrum of the jet and its detailed spatial structure, and on the properties of the counterjet, we argue that inverse-Compton models can be conclusively rejected, and propose that the X-ray emission from the jet is synchrotron emission from particles accelerated in the boundary layer of a relativistic jet. For the first time, we find evidence that the bright western hotspot is also time-varying in X-rays, and we connect this to the small-scale structure in the hotspot seen in high-resolution radio observations. The new data allow us to confirm that the spectrum of the lobes is in good agreement with the predictions of an inverse-Compton model and we show that the data favour models in which the filaments seen in the radio images are predominantly the result of spatial variation of magnetic fields in the presence of a relatively uniform electron distribution.

show abstract

Optical Detection of the Pictor a Jet and Tidal Tail: Evidence Against an Ic/CMB Jet

Cited by 10 publications

References 24 publications

Integral field spectroscopy of the circum-nuclear region of the radio Galaxy Pictor A

Integral field spectroscopy of the circum-nuclear region of the radio Galaxy Pictor A

The Spectacular Radio-Near-Ir-X-Ray Jet of 3c 111: The X-Ray Emission Mechanism and Jet Kinematics

DeepChandraobservations of Pictor A

Contact Info

Product

Resources

About