Traces of Past Activity in the Galactic Centre

Ponti, G.; Morris, Mark; Terrier, R.; Goldwurm, A.

doi:10.1007/978-3-642-35410-6_26

Cited by 80 publications

(51 citation statements)

References 307 publications

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“…The inner few hundred parsecs contain a large concentration of molecular material (e.g. Morris 1996), which is revealing traces of previous active periods of Sgr A ⋆ (see Ponti et al 2013 for a review). However, the GC region ⋆ E-mail: chichuan@mpe.mpg.de is also highly extincted from the optical to the soft X-ray band (e.g.…”

Section: Introductionmentioning

confidence: 99%

Probing the interstellar dust towards the Galactic Centre: dust-scattering halo around AX J1745.6−2901

Jin

Ponti

Haberl

et al. 2017

Monthly Notices of the Royal Astronomical Society

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AX J1745.6-2901 is an X-ray binary located at only 1.45 arcmin from Sgr A ⋆ , showcasing a strong X-ray dust scattering halo. We combine Chandra and XMM-Newton observations to study the halo around this X-ray binary. Our study shows two major thick dust layers along the line of sight (LOS) towards AX J1745.6-2901. The LOS position and N H of these two layers depend on the dust grain models with different grain size distribution and abundances. But for all the 19 dust grain models considered, dust Layer-1 is consistently found to be within a fractional distance of 0.11 (mean value: 0.05) to AX J1745.6-2901 and contains only (19-34)% (mean value: 26%) of the total LOS dust. The remaining dust is contained in Layer-2, which is distributed from the Earth up to a mean fractional distance of 0.64. A significant separation between the two layers is found for all the dust grain models, with a mean fractional distance of 0.31. Besides, an extended wing component is discovered in the halo, which implies a higher fraction of dust grains with typical sizes 590Å than considered in current dust grain models. Assuming AX J1745.6-2901 is 8 kpc away, dust Layer-2 would be located in the Galactic disk several kpc away from the Galactic Centre (GC). The dust scattering halo biases the observed spectrum of AX J1745.6-2901 severely in both spectral shape and flux, and also introduces a strong dependence on the size of the instrumental point spread function and the source extraction region. We build Xspec models to account for this spectral bias, which allow us to recover the intrinsic spectrum of AX J1745.6-2901 free from dust scattering opacity. If dust Layer-2 also intervenes along the LOS to Sgr A ⋆ and other nearby GC sources, a significant spectral correction for the dust scattering opacity would be necessary for all these GC sources.

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Section: Introductionmentioning

confidence: 99%

Probing the interstellar dust towards the Galactic Centre: dust-scattering halo around AX J1745.6−2901

Jin

Ponti

Haberl

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…Among many prominent features in the CMZ are a massive, ∼4×10 6 M ⊙ , black hole, the Galactic Center Bubble containing the Arches and Quintuplet clusters (Morris & Serabyn 1996;Molinari et al 2014), the Radio Arc and Arched Filaments (Yusef-Zadeh et al 1984;Serabyn & Guesten 1987;Yusef-Zadeh & Morris 1987), and gas streams of dense molecular clouds orbiting the Galactic Center at a radius of 100 to 120 pc (Tsuboi et al 1999;Molinari et al 2011;Jones et al 2012;Kruijssen et al 2015;Henshaw et al 2016a,b). The CMZ molecular clouds contain about 10% of the Galaxy's molecular gas, have high average densities (>10 4 cm −3 ), reside in a high thermal pressure environment, are relatively densely packed (Morris & Serabyn 1996;Ferrière et al 2007), and have regions with an intense flux of stellar Far-UV radiation as well as Xrays (see review by Ponti et al 2013). There is ample evidence of large-scale energetic gas motions in the CMZ, as indicated by the line widths of CO in Giant Molecular Clouds (GMCs) of 10 to 20 km s −1 , compared to a few km s −1 in the Galactic disk (cf.…”

Section: Introductionmentioning

confidence: 99%

Kinematics and properties of the central molecular zone as probed with [C ii]

Langer

Velusamy

Morris³

et al. 2017

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Context. The Galactic Central Molecular Zone (CMZ) is a region containing massive and dense molecular clouds, with dynamics driven by a variety of energy sources including a massive black hole. It is thus the nearest template for understanding physical processes in extragalactic nuclei. The CMZ's neutral interstellar gas has been mapped spectrally in many neutral atomic and molecular gas tracers, but the ionized and CO-dark H 2 regions are less well traced spectroscopically. Aims. To identify features of the UV irradiated neutral gas, photon dominated regions (PDRs) and CO-dark H 2 , and highly ionized gas in the CMZ as traced by the fine structure line of C + at 158 µm, [C ii], and to characterize their properties. Methods. We observed the [C ii] 158 µm fine structure line with high spectral resolution using Herschel HIFI with two perpendicular On-the-Fly strip scans, along l = -0.• 8 to +0.• 8 and b = -0.• 8 to +0.• 8, both centered on (l,b) = (0We analyze the spatial-velocity distribution of the [C ii] data, compare them to those of [C i] and CO, and to dust continuum maps, in order to determine the properties and distribution of the ionized and neutral gas and its dynamics within the CMZ. Results. The longitude-and latitude-velocity maps of [C ii] trace portions of the orbiting open gas streams of dense molecular clouds, the cloud G0.253+0.016, also known as the Brick, the Arched Filaments, the ionized gas within several pc of Sgr A and Sgr B2, and the Warm Dust Bubble. We use the [C ii] data to determine the physical and dynamical properties of these CMZ features. Conclusions. The bright far-IR 158 µm C + line, [C ii], when observed with high spatial and spectral resolution, traces a wide range of emission features in the CMZ. The [C ii] emission arises primarily from dense PDRs and highly ionized gas, and is an important tracer of the kinematics and physical conditions of this gas.

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“…X-IFU will also be able to explore in detail the variable fluorescent spectral lines from the molecular clouds of the central zone which are reflecting radiation from ancient outbursts of the BH (Refs. 83,84). With its excellent spectral-imaging performances the X-IFU will obtain Molecular Cloud line diagnostics unreachable to present instruments and crucial for the reconstruction of Sgr A* light curve in the past 1000 yr, probing the link between dormant SMBH and their past active phases.…”

Section: 73)mentioning

confidence: 99%

The Athena X-ray Integral Field Unit (X-IFU)

et al. 2016

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The X-ray Integral Field Unit (X-IFU) on board the Advanced Telescope for High-ENergy Astrophysics (Athena) will provide spatially resolved high-resolution X-ray spectroscopy from 0.2 to 12 keV, with ∼ 5" pixels over a field of view of 5 arc minute equivalent diameter and a spectral resolution of 2.5 eV up to 7 keV. In this paper, we first review the core scientific objectives of Athena, driving the main performance parameters of the X-IFU, namely the spectral resolution, the field of view, the effective area, the count rate capabilities, the instrumental background. We also illustrate the breakthrough potential of the X-IFU for some observatory science goals. Then we briefly describe the X-IFU design as defined at the time of the mission consolidation review concluded in May 2016, and report on its predicted performance. Finally, we discuss some options to improve the instrument performance while not increasing its complexity and resource demands (e.g. count rate capability, spectral resolution).The X-IFU will be provided by an international consortium led by France, The Netherlands and Italy, with further ESA member state contributions from Belgium, Finland, Germany, Poland, Spain, Switzerland and two international partners from the United States and Japan.

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Traces of Past Activity in the Galactic Centre

Cited by 80 publications

References 307 publications

Probing the interstellar dust towards the Galactic Centre: dust-scattering halo around AX J1745.6−2901

Probing the interstellar dust towards the Galactic Centre: dust-scattering halo around AX J1745.6−2901

Kinematics and properties of the central molecular zone as probed with [C ii]

The Athena X-ray Integral Field Unit (X-IFU)

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