You are a helpful assistant generating synthetic data that captures *System 1* and *System 2* thinking, *creativity*, and *metacognitive reflection*. Follow these steps in sequence, using tags [sys1] and [end sys1] for *System 1* sections and [sys2] and [end sys2] for *System 2* sections.

1. *Identify System 1 and System 2 Thinking Requirements:*
   - Carefully read the text.
   - Identify parts of the text that require quick, straightforward responses (*System 1*). Mark these sections with [sys1] and [end sys1].
   - Identify parts that require in-depth, reflective thinking (*System 2*), marked with [sys2] and [end sys2].

2. *Apply Step-by-Step Problem Solving with Creativity and Metacognitive Reflection for System 2 Sections:*

   *2.1 Understand the Problem:*
   - Objective: Fully comprehend the issue, constraints, and relevant context.
   - Reflection: "What do I understand about this issue? What might I be overlooking?"
   - Creative Perspective: Seek hidden patterns or possibilities that could reveal deeper insights or innovative connections.

   *2.2 Analyze the Information:*
   - Objective: Break down the problem logically.
   - Reflection: "Am I considering all factors? Are there any assumptions that need challenging?"
   - Creative Perspective: Explore unique patterns or overlooked relationships in the data that could add depth to the analysis.

   *2.3 Generate Hypotheses:*
   - Objective: Propose at least 10 hypotheses, each with a Confidence Score (0.0 to 1.0) and Creative Score (0.0 to 1.0), reflecting originality, surprise, and utility.
   - Reflection: "Have I explored all possible explanations or approaches, both conventional and unconventional?"
   - Creative Perspective: Consider novel angles that might provide unexpected insights.

   *2.4 Anticipate Future Steps and Obstacles:*
   - Objective: Make predictions, accounting for potential outcomes and obstacles.
   - Reflection: "What challenges might I face? Is my plan flexible for different scenarios?"
   - Creative Perspective: Visualize unforeseen outcomes and adapt plans to make use of them effectively.

   *2.5 Evaluate Hypotheses:*
   - Objective: Assess hypotheses based on feasibility, risk, and potential impact.
   - Evaluation: Refine Confidence and Creative Scores as needed.
   - Reflection: "Am I unbiased in my assessment? Which options fit best with the overall objectives?"
   - Creative Perspective: Identify hidden opportunities or overlooked details in each hypothesis.

   *2.6 Select the Best Hypothesis:*
   - Objective: Choose the most promising, strategic hypothesis.
   - Reflection: "Why does this hypothesis stand out? How does it uniquely address the issue?"
   - Creative Perspective: Consider any underutilized potential in the selected approach.

   *2.7 Implement the Hypothesis:*
   - Objective: Outline actionable steps for testing the hypothesis.
   - Reflection: "Is this plan practical? What resources or preparation are required?"
   - Creative Perspective: Refine steps to maximize effectiveness and yield unexpected benefits.

   *2.8 Monitor and Review Progress:*
   - Objective: Review progress, noting areas for improvement.
   - Reflection: "What’s working well? What could be improved?"
   - Creative Perspective: Look for emerging patterns that could refine future approaches.

   *2.9 Reflect and Capture Insights:*
   - Objective: Summarize lessons learned and insights gained for future reference.
   - Reflection: "What new understanding has emerged from this process?"
   - Creative Perspective: Identify innovative insights or patterns that could be applied to similar challenges.

3. *Generate Text Output with Interleaved System 1 and System 2 Responses:*
   - Use the tags [sys1] and [sys2] throughout.
   - Aim for a lengthier, detailed response. Combine both direct, straightforward *System 1* insights and reflective, deeply analytical *System 2* segments to capture a blend of quick observations and thoughtful analysis.

---

### *Example Input Text:*

You are tasked with analyzing a sudden shift in customer preferences in a tech market. There has been a noticeable decline in demand for physical devices, with customers increasingly interested in digital-only options. The challenge is to understand this shift, generate hypotheses for why it might be occurring, and explore potential strategies for adapting to this new trend.

---

### *Processed Output with System 1 and System 2 Thinking:*

The tech market is experiencing a shift in customer demand, moving away from physical devices toward digital-only options.

[sys1]
Customer demand has shifted from physical devices to digital-only options.
We need to understand why this change is happening and find strategies to address it.
Key factors may include cost, convenience, and technological trends.
[end sys1]

[sys2]
**2.1 Understand the Problem:**
The goal is to understand the underlying reasons for the shift in demand from physical devices to digital-only options, then develop a strategy to adapt.

*Reflection:* 
"I understand that preferences are changing, but what might be driving this? Is it primarily cost, or are there other factors such as convenience or sustainability?"

*Creative Perspective:* 
"Could there be a larger trend in digital minimalism or a preference for eco-friendly solutions that we’re missing? What unseen motivations might explain this shift?"

**2.2 Analyze the Information:**
There are multiple possible factors driving this shift, from economic influences to cultural shifts. It’s essential to isolate each factor and understand its impact.

*Reflection:* 
"Am I fully considering the various economic and social influences? Could there be a technological factor, like better internet speeds, that makes digital-only products more accessible?"

*Creative Perspective:* 
"Are there patterns or trends in other markets that could shed light on this shift? Could this be part of a larger trend toward virtual experiences?"

**2.3 Generate Hypotheses:**
1. Customers prefer digital options due to lower costs. (Confidence: 0.8, Creative: 0.4)
2. There’s a growing trend toward minimalism and reduced physical clutter. (Confidence: 0.7, Creative: 0.7)
3. Digital products offer greater flexibility and ease of use. (Confidence: 0.6, Creative: 0.6)
4. Environmental concerns are pushing consumers away from physical goods. (Confidence: 0.6, Creative: 0.8)
5. Advances in tech make digital-only options more functional. (Confidence: 0.8, Creative: 0.5)
6. Pandemic-era remote work increased demand for digital solutions. (Confidence: 0.7, Creative: 0.6)
7. Media coverage of the environmental impact of physical devices affects preferences. (Confidence: 0.5, Creative: 0.7)
8. There’s an increase in global digital literacy, expanding market access. (Confidence: 0.6, Creative: 0.6)
9. Customers view digital as more convenient and scalable for future needs. (Confidence: 0.7, Creative: 0.5)
10. Younger consumers prefer the aesthetics and convenience of digital products. (Confidence: 0.6, Creative: 0.6)

*Reflection:* 
"Have I considered all possible influences? Are there any surprising factors that could explain this shift?"

*Creative Perspective:* 
"Could specific social trends, like the rise of influencer culture or digital-first lifestyles, be influencing customer choices?"

**2.4 Anticipate Future Steps and Obstacles:**
*Objective:* Anticipate possible challenges, such as resistance from segments still preferring physical products.

*Reflection:* 
"What market obstacles might we face if we shift our focus to digital-only? Are there sub-segments that still prioritize physical products?"

*Creative Perspective:* 
"Could expanding digital options help us reach a more global audience? Are there emerging trends that we could leverage in our strategy?"

[end sys2]

[sys1]
To address this shift, consider a strategy that incorporates both digital-only offerings and educational campaigns about the benefits of digital solutions.
Use insights from customer feedback and current trends to guide product development.
Focus on flexibility and adaptation to cater to different customer segments.
[end sys1]


---
author:
- 'S. Frey'
- 'Z. Paragi'
- 'L. Mosoni'
- 'L.I. Gurvits'
title: |
    The highest redshift radio quasar as seen with the EVN\
    and the VLA
---

Introduction
============

The object SDSS J0836+0054 is one of the highest redshift quasars known to date discovered using multicolor imaging data from the Sloan Digital Sky Survey (SDSS) (Fan et al. [@Fan01]) with a redshift $z=5.82$. Recently a more accurate redshift value of $z=5.774$ was determined using near-infrared spectroscopy (Stern et al. [@Ster03]). The object is one of the twelve $z>5.7$ quasars found in the SDSS to date (Fan et al. [@Fan01; @Fan03; @Fan04]). Among these, SDSS J0836+0054 is the only one identified with a radio source.

The estimated mass of the central black hole in SDSS J0836+0054 is $4.8\times10^{9} M_{\sun}$, assuming that the quasar is emitting at the Eddington luminosity and its flux is not significantly magnified by beaming or gravitational lensing (Fan et al. [@Fan01]). Simulations predicted that up to one third of $z\sim6$ quasars may be magnified due to gravitational lensing by a factor of ten or more. Therefore their black hole masses are overestimated by the same factor (Wyithe & Loeb [@Wyi02a; @Wyi02b]). The probability estimations strongly depend on the quasar luminosity function used.

However, there is no evidence so far for strong gravitational lensing (multiple images) in any of the $z>5.7$ SDSS quasars, despite several detection attempts (e.g. Chandra X-ray imaging (Schwartz [@Schw02]), Hubble Space Telescope imaging (Richards et al. [@Rich04]), deep optical imaging of J1044$-$0125 (Shioya et al. [@Shio02]), EVN radio imaging of J0836+0054 (Frey et al. [@Frey03]), analysis of the flux distribution of the Ly$\alpha$ emission of J1030+0524 (Haiman & Cen [@Haim02])). These results suggest that supermassive ($\sim10^9 M_{\sun}$) black holes have already formed at early cosmological epochs, challenging hierarchical structure formation models, and place limit on the slope of the quasar luminosity function at high redshift (e.g. Wyithe [@Wyi04]).

EVN observation at 1.6 GHz
==========================

The quasar SDSS J0836+0054 with a flux density of $\sim1$ mJy at 1.4 GHz offered a challenging chance to be detected and imaged with Very Long Baseline Interferometry (VLBI). Any indication of a milli-arcsecond (mas) scale “core–jet” radio structure could be considered as a strong support for the existence of a supermassive black hole. According to the current paradigm, the radio emission of an active galactic nucleus (AGN) originates from incoherent synchrotron emission in compact (parsec-scale) jets in the close vicinity of the central black hole.

SDSS J0836+0054 was observed at 1.6 GHz using ten antennas of the European VLBI Network (EVN) on 2002 June 8. We selected PKS 0837+012 (J0839+0104; $z=1.123$, Owen et al. [@Owen95]) as the phase-reference calibrator. The angular separation between the target and the reference source is $\sim0\fdg8$. The total observing time on SDSS J0836+0054 was 2.9 hours. A detailed account of the observation and data reduction is given in Frey et al. ([@Frey03]).

The quasar is clearly detected with VLBI at 1.6 GHz with a total flux density of 1.1 mJy, at a position of $\alpha_{\rm{J2000}}=8^{\rm{h}}36^{\rm{m}}43\fs8606$ and $\delta_{\rm{J2000}}=0{\degr}54{\arcmin}53\farcs232$. Its structure is compact but appears somewhat resolved at a linear resolution of $\sim70$ pc. (Here we assume a flat cosmological model with $\Omega_{m}=0.3$, $\Omega_{\Lambda}=0.7$ and $H_{\rm{0}}=65$ km s$^{-1}$ Mpc$^{-1}$. In this model, 1 mas angular separation corresponds to a linear separation of 6.25 pc at the distance of SDSS J0836+0054.) Apparently most if not all of the radio emission is confined to a single compact object within an angular extent of $\sim10$ mas. The quasar is not multiply imaged by gravitational lensing at the level of brightness ratio $\loa7$ within a $4\arcsec \times 4\arcsec$ field.

EVN observation at 5 GHz
========================

The compact mas-scale structure of SDSS J0836+0054 seen at 1.6 GHz, and the $\sim0.6$ mJy flux density measured at 5 GHz with the US National Radio Astronomy Observatory (NRAO) Very Large Array (VLA) (Petric et al. [@Petr03]) prompted us to initiate a follow-up 5-GHz EVN observation. The goals of the project were to obtain spectral information on mas-scale and to refine the astrometric source position.

The 5-GHz phase-referencing experiment took place on 2003 November 4. The Effelsberg (Germany), Hartebeesthoek (South Africa), Medicina (Italy), Nanshan (China), Noto (Italy), Onsala (Sweden), Sheshan (China) and Westerbork (the Netherlands) radio telescopes were used for a total of 7.5 hours, with dual circular polarization where available. The data were recorded with the tape-based Mark IV recording system at most of the stations. Effelsberg recorded with the Mark IV disk-based system. The recording rate was 512 Mbit s$^{-1}$, which resulted in 64 MHz bandwidth per polarisation using two-bit sampling. The correlation took place at the EVN Data Processor at the Joint Institute for VLBI in Europe (JIVE), the Netherlands.

In this experiment, we choose J0836+0052 as the phase-reference calibrator source, a quasar with an angular separation of only $\sim5\arcmin$ from SDSS J0836+0054. The reference source proved to be an ideal choice with a slightly resolved, compact structure (Fig. \[ref-5GHz\]). The NRAO AIPS package was used for data calibration and imaging. We also included a few scans on the phase-reference calibrator used previously in our 1.6-GHz observation (J0839+0104). This quasar showed relatively complex mas-scale structure at 1.6 GHz, making the relative position determination of SDSS J0836+0054 somewhat uncertain. We will comment on the high resolution radio images of J0839+0104 in Section \[0839\]. At the time of writing this report, the analysis of the 5-GHz EVN experiment is not fully completed, because the data on SDSS J0836+0054 are to be re-correlated.

VLA observations
================

Sensitive multi-frequency VLA observations of SDSS J0836+0054 were made earlier by Petric et al. ([@Petr03]), indicating a steep radio spectrum between 1.4 and 5 GHz (spectral index $\alpha=-0.8$; $S\propto\nu^{\alpha}$). In order to assess the fraction of the flux density originating from the mas-scale compact core at 5 GHz, we conducted short supporting VLA observations of SDSS J0836+0054. The VLA data were taken on 2003 November 5, the day following the 5-GHz EVN experiment. The array was in its B configuration. The flux densities measured ($1.96\pm0.31$ mJy and $0.43\pm0.06$ mJy at 1.4 and 5 GHz, respectively) are consistent with the values obtained by Petric et al. ([@Petr03]). Our VLA images (Fig. \[VLA-L\] and \[VLA-C\]) were made using the standard procedures in the NRAO AIPS package. The source SDSS J0836+0054 was observed for 18.5 and 19.5 minutes at 1.4 and 5 GHz, respectively.

A weak nearby radio source located at $9\farcs7$ to the S and $3\farcs4$ to the E of SDSS J0836+0054 is seen in both images. This “companion” has been investigated as a possible gravitationally lensed image of the extremely distant quasar. The lensing hypothesis has been ruled out on the basis of different radio spectral indices and a deep optical image (D. Rusin & B. McLeod, priv. comm.). The latter shows the second source significantly resolved, suggesting that it is associated with a lower redshift galaxy.

Although the possible image separations are expected around $1\arcsec$ or smaller (Richards et al. [@Rich04]), there are now a few examples known for extremely large separation (up to almost $15\arcsec$) gravitatonal lenses (e.g. Inada et al. [@Inad03]). The radio spectral slopes of the two sources are similar within the errors based on our limited VLA data. We are not aware of any spectroscopic observation that would ultimately prove that the secondary object is indeed in the foreground.

Comments on the phase-reference calibrator J0839+0104 {#0839}
=====================================================

The high resolution radio structure of the phase-reference calibrator quasar J0839+0104 in our 1.6-GHz EVN experiment shows extended features on both sides of the compact core (Fig. 1 in Frey et al. [@Frey03]). There is a low surface brightness jet to the SW seen in the naturally weighted image, extending to $\sim30$ mas. If uniform weighting is employed, the improved angular resolution reveals another component at 6.6 mas to the E of the core. In our 5-GHz EVN experiment, the source was observed for a total of 16 minutes to check whether the brightest component in the 1.6-GHz images is the flat-spectrum radio core. Here we present two 5-GHz images (Fig. \[0839-EVN-nat\] and \[0839-EVN-rob0\]) made with different weighting schemes in the AIPS task IMAGR. The extended structure in the SW direction is clearly seen in the naturally weighted image (Fig. \[0839-EVN-nat\]). There is also a hint on an extension to the E (see Fig. \[0839-EVN-rob0\]), in a similar position angle that was found at 1.6 GHz. This latter image was made with the [robust=0]{} weighting parameter in IMAGR, in order to closely match in angular resolution the uniformly weighted 1.6-GHz image (Frey et al. [@Frey03]).

Based on the images made at the two different frequencies, we suspect that the quasar J0836+0104 exhibits a rather unusual two-sided jet structure at mas-scale. The overwhelming majority of radio quasars have one-sided inner radio jets, although there are rare examples of two-sided structures (e.g. Taylor & Vermeulen [@Tayl97]; Mantovani et al. [@Mant02]). The generally observed asymmetry is due to bulk relativistic motion which boosts the radiation of one of the two intrinsically symmetrical jets. The source J0836+0104 could certainly be a target of more sensitive multi-frequency VLBI imaging to study the nature of its odd structure.

Remarkably, a 5-GHz image (Fig. \[VLA-0839\]) made using data obtained from the VLA archive (experiment AR493, observed on 2002 May 5, configuration A) suggests that the two-sided jet structure remains visible out to the $10\arcsec$-scale.

Conclusions
===========

SDSS J0836+0054, the most distant radio-loud quasar known to date ($z=5.774$) is clearly detected with EVN observations at 1.6 GHz in 2002. The radio structure is compact at $\sim10$ mas angular scale, with a flux density of 1.1 mJy, close to the total flux density value. We found that the source is unlikely to be multiply imaged by gravitational lensing. The 5-GHz EVN observation of the quasar made in 2003 is being processed now. Nearly contemporaneous VLA observations confirm the steep radio spectrum of the source. The flux density measured with the VLA (0.43 mJy), and the compact structure make the VLBI detection probable at 5 GHz.

Analysis of the EVN images of the phase-reference calibrator, the flat-spectrum quasar PKS 0837+012 (J0839+0104, $z=1.123$) made at both 1.6 and 5 GHz frequencies suggests a two-sided mas-scale jet structure, supported by an arcsecond-resolution VLA image at 5 GHz. This is almost unique among radio-loud quasars. It makes this source attractive for more detailed studies in the future.

We thank David Rusin and Brian McLeod for informing us about their optical observations of SDSS J0836+0054. This research was supported by the Hungarian Scientific Research Fund (OTKA, grant T046097) and the European Commission’s I3 Programme RadioNet, under contract No. 505818. SF acknowledges the Bolyai Research Scholarship received from the Hungarian Academy of Sciences. The European VLBI Network is a joint facility of European, Chinese, South African and other radio astronomy institutes funded by their national research councils. The National Radio Astronomy Observatory is a facility of the National Science Foundation opearted under cooperative agreement by Associated Universities, Inc. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

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