High resolution x ray spectroscopic constraints on cooling flow models
1 / 25

High Resolution X-ray Spectroscopic Constraints on Cooling-Flow Models - PowerPoint PPT Presentation

  • Uploaded on

High Resolution X-ray Spectroscopic Constraints on Cooling-Flow Models. John Peterson, Steven Kahn, Frits Paerels (Columbia); Jelle Kaastra, Takayuki Tamura, Johan Bleeker, Carlo Ferrigno (SRON); Garrett Jernigan (Berkeley). Cooling Flows.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about ' High Resolution X-ray Spectroscopic Constraints on Cooling-Flow Models' - adila

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
High resolution x ray spectroscopic constraints on cooling flow models

High ResolutionX-ray Spectroscopic Constraintson Cooling-Flow Models

John Peterson,

Steven Kahn, Frits Paerels (Columbia);

Jelle Kaastra,

Takayuki Tamura, Johan Bleeker, Carlo Ferrigno (SRON);

Garrett Jernigan (Berkeley)

Cooling flows
Cooling Flows

  • Long-standing prediction that cores of clusters should cool by emitting X-rays in less than a Gyr =>Range of Temperatures

  • Differential Luminosity predicted to be:dLx=5/2 (Mass Deposition Rate) k/(mp) dT

  • Predicts a unique X-ray spectrum; Free parameters: Tmax, Abundances, Mass Deposition Rate


X-ray Luminosity is

heat loss

No heating


Extra assumptions: atomic physics determines L and T,

Locally maxwellian, no absorption, metal distribution,

Exact prediction for mdot depends on grav. potential

Measuring a differential luminosity at keV temperatures

=> Need Fe L ions (temperature sensitive)

=> Need to resolve each ion separately (i.e. / ~ 100)

Very difficult to do in detail with CCD instrument

(ASCA, XMM-Newton EPIC, Chandra ACIS)

Works with XMM-Newton RGS (for subtle reasons)

RGS (dispersive spectrometer) :

High dispersion angles (3 degrees) for XMM PSF

/ ~ 3 degrees / ang. size ~ 100 for arcminute size

Soft X-ray band from Si K to C K; 5 to 38 angstroms

FOV: 5 arcminutes by 1 degree

Analysis not simple: dispersive, background, few counts

Failure of the model
Failure of the Model

8 keV  3 keV  ?

Peterson et al. 2001

Warm Clusters (2-4 keV):


Very weak Fe XVIII-XX

Cool Clusters/Groups

(1 to 2 keV):

Some Fe XVII,

Fe XVII not any stronger

Than Fe XVIII,



into temperature


Put multiphase

region in a

3-d envelope


the normalization

of each bin

to get a

limit on Mdot

16 free




Differential Luminosity vs.

Fractional Temperature

Differential Luminosity vs. Temperature

Differential Luminosity ~ T

 ~ 1 to 2

Observational Results

1. Sub Tmax plasma always there

2. Model fails at a fraction of Tmax rather than fixed T~1keV

3. Model fails in shape as well as normalization;

Tilted toward higher temperatures

Overall normalization

difficult to interpret w/o model

5. Some scatter in both slope and normalization (unknown if this is a real difference)

6. Unclear if relation continues to low temperature for all

clusters or not

Limits as strong as a factor of 10

T cutoff is oversimplified;

small mdot is oversimplified too

Theoretical Intepretation: Essentially Three Fine-tuning Problems


Can find ways to add heat or subtract heat (through

additional non x-ray luminosity), but…

1. Energetics: Need average heating or cooling power ~ Lx

Coolants: Dust (IR), Cold clouds (UV), particles

Heating: AGN mech. energy+particles, mergers,

outer regions via conduction

Affects the normalization of the diff. luminosity plot

Dynamics: Either need energy source to work at low temperatures or at t ~ tcool (before complete cooling would occur)

Cooling time ~ T2 / (cooling function)

If at 1/3 Tmax then why cool for 8/9 of the cooling time?

or why at low temperatures?

Affects the fractional temperature where problem occurs

  • Get Energetic and Dynamics right at all spatial positions temperatures or at t ~ t

    Observational situation is not fully worked out

    Soft X-rays missing throughout entire cflow volume

    Steep differential luminosity distribution difficult

    partly spatially stratified/partly intrinsic steep distribution

  • (See Kaastra’s talk)

Perseus Cluster temperatures or at t ~ t

Perseus temperatures or at t ~ t

at 5





Perseus: temperatures or at t ~ t

Differential luminosity of the inner 3.5 arcminutes

4 actual cooling flows: temperatures or at t ~ t

Mukai, Kinkhabwala, Peterson, Kahn, Paerels 2003

Conclusions temperatures or at t ~ t

Cooling flow model fails to reproduce X-ray spectrum; Several strong observational constraints

Much more theoretical work needed for fine-tuning challenges

Much more observational work is needed to constrain the spatial distribution and to connect to other wavelengths